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V8 Dakotas
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varnuke
Dodge Dakota
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10/11/2003
20:32:29
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 Subject: RE: 4.7liter Overheating - Case History
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New radiator installed and new belt tensioner installed.
Dally and Allan, it looks like the radiator was the final solution. Should have initially approached the Dodge service manager and he might have saved me from buying an extra thermostat and new fan clutch with his infrared hand-held thermometer.
All in all, new pump, belt, thermostat, fan clutch, belt tensioner, and radiator, and it seems to be working just like brand new again. Will test it out tomorrow on the hills.
Will take some time to write up the procedure for changing it out, as it took me just about 5 hours to get it all done. Now that I have done it once, doing it again would only probably take 2.5-3.5 hours knowing all the right tools and extra materials to have ready to do a neat and clean job of it from start to finish.
Not sure how much it would have cost to have a dealer replace all of these items, but for approximately $600 total in parts, it is all on there and working properly again.
If there is anyone who is interested in having the procedure written up, let me know. I'll take the time to do it and post it. There are guite a few responding here that apparently already know how to do all of this relatively simple stuff. It makes me feel like I am posting on a forum used almost exclusively by professional Dodge mechanics.
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varnuke
Dodge Dakota
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10/11/2003
23:57:15
| RE: 4.7liter Overheating - Case History
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SUMMARY - Case History 4.7Liter Overheating - With Detailed Repair Procedures
[Here it is anyway while fresh in my mind. The way I did it.]
2000 Dakota Club Cab, 4x4, 4.7liter w/auto transmission, limited slip differential (LSD), heavy duty everything. Mobil 1 10W-30 engine oil, Mobil 1 in LSD. Approximately 164,000 miles when overheating problem kept my attention. My truck could normally pull the mountains between LA and Las Vegas in the summer with air conditioning on full blast, accelerating uphills without overheating, but this last year I had to turn off the air conditioning and turn on the heater full blast when pulling the same hills last summer to keep from overheating.
The main components to check in the engine cooling system are the Serpentine belt, belt tensioner, thermostat, water pump, mechanical fan viscous clutch, radiator, overflow/suction coolant tank, radiator cap, and hoses. There is no bypass hose on this 4.7L system from the water pump housing.
SERPENTINE BELT
My truck still had all the orginal equipment on it when the overheating problem was noted. The Serpentine belt, according to another poster is suppose to have a lifetime of approximately 80,000 miles before it should be replaced. Mine had 164,000 miles on it, and the backside, which is the side that drives the water pump pulley, was very smooth like a sheet of glass appearance instead of the rubbery surface it should have for good friction contact on the water pump pulley to drive it.
SERPENTINE BELT REMOVAL - INSTALL PROCEDURE
This belt can be changed in less than a minute. It is first easier to take the winshield wash fluid tank and radiator overflow tank off so you have full access to these components. To get the tank out of the way, get a 10mm socket, a ratchet and two different lengths of extensions to make it easier. There are two 10mm bolts on each side of this tank combination. After you remove these bolts, disconnect the two electrical sensor connectors on the left hand side of the tank (that is passenger side - looking from front to back). There is also a small rubber hose at the bottom of aft electrical connection (white) component that you have to disconnect by pulling it off. When you take this off windshield washer fluid will come out if that tank is not empty. You can empty any fluids in these tanks by using a turkey baster, if necessary. Otherwise just put your finger over the outlet and lift the tanks up and over to the right side of the engine compartment, tilted so that the washer fluid does not come out of the port. Leave the radiator overflow hose connected and stand or position the tanks so they are out of the way. Then take a wrench with a 15mm socket on it and put it on the nut in the center of the tensioner pulley. Swing the wrench handle toward the right side (driver's side) of the engine compartment to take the tension off the belt. Then remove the belt from the tensioner line of swing. The belt can then be removed from all the pulleys and taken off over the fan. [I had the mechanical fan off too, but I think you need not remove the fan blade to get the belt off and out. I removed the fan using a large Crescent wrench on the large nut attached to the fan viscous clutch. Put the Crescent wrench on the nut using one of the two large openings in the blades. Then have someone put some pressure on the Serpentine belt by pushing on it with a wrench from the left-hand side of the engine compartment to help keep the water pump pulley from turning. Then smack the Crescent wrench with a hammer smartly and the nut should come loose. Turn the fan counterclockwise and the nut will unscrew off the water pump pulley shaft. Be careful when you get to the end of the threads so that you don't drop the fan and clutch assembly where it could damage something below.]
BELT TENSIONER
The other thing to check is the belt tensioner which is on the lower left side of the front of the engine. If you take and pull on the belt toward the passenger side of the truck, you can move the tensioner pulley in and out to feel if it moves smoothly along it travel. Mine would have a little "catch" at a certain position. The tension was probably still good enough overall, but the little "catch" was not good in my opinion.
BELT TENSIIONER REMOVAL - INSTALL PROCEDURE
The belt tensioner is an assembly with an idler pulley attached to it. There is a 14mm bolt on center body of the belt tensioner. By removing this 14mm bolt, you can remove the assembly as one piece. On the backside there is a cutout tha fit over another bolt head or nut to keep the tensioner body from rotating. Reinstall the new tensioner so the cutout fits over this bolt or nut head and replace the 14mm bolt that holds it in place.
THERMOSTAT REMOVAL - INSTALL PROCEDURE
The thermostat is located at the bottom left of the engine where the inlet hose from the radiator is attached. There are two 8mm bolts holding the hose fitting wherein the thermostate is located. The original equipment thermostat can only be inserted into this "sandwich" one way because if you put it in the wrong way it will hit the hose fitting and you will not be able to bolt the hose fitting back on. If you remove these two 8mm bolts, you will get a lot of fluid coming out too, so have a large tub ready to catch the coolant underneath. The thermostat comes with it own rubberized gasket that fits around the circular mounting plate of the thermostat. I could not find a replacement thermostat from any auto supply shop and had to go to a Dodge dealer for this part. Thermostats have been known to stick, but I have not seen one for this Dakota engine stick yet.
WATER PUMP
The water pump is an assembly that comes with a new compressible rubber gasket already installed, if you purchase it from a Dodge parts dealer. The pump impeller is made of a plastic material and should last the lifetime of the engine, as I saw no degredation at all from my impeller as compared to the brand new pump impeller. The diffuser vanes were not worn or eroded at all. The bearings did not sound or appear to be bad until I spun the pump pulley as fast as I could by hand, when i noticed it had some radial play between the shaft and housing. It probalby would have gone quite a few more miles before the bearings completely failed, as there was no noticeable noise from them at speed at all.
WATER PUMP REMOVAL - INSTALL PROCEDURE
Remove the idler pulley off the belt tensioner to completely expose the water pump housing. There are eight 15mm bolts that hold the water pump onto the front of the engine. One of these bolts has a stud and nut that you will need a deeper 15mm socket to get off with a wratchet. I found it convenient to put the bolts into the same holes in the new pump housing so they don't get mixed up, because some of them are much longer than the others. This way you put them back into the same holes they came out of initially.
VISCOUS FAN CLUTCH
The mechanical fan clutch allows the fan to freewheel when the engine is cool starting up and when you are at speed on the highway and the air flow into the radiator is more than sufficient to cool down the system. When the engine is hot and you are at a stand still, the mechanical fan should be working full force. There is a good flow of forceful air to be felt from this fan when you lift the hood of the engine compartment. My fan clutch was still good, but because of the miles on it there was a packed situation of dirt and bugs in between the bimetalic strip on the front end of the clutch housing. I'm not sure how this mechanism works, but suspect that movement of the bimetalic strip has something to do with the engaging of the clutch as the temperature rises. With the spring-looking-like bimetallic strip completely packed with dirt, grime and bugs, it could not contract and expand properly as designed. So, at least clean this out with a good blast of air and water so that bimetallic strip can operate correctly.
VISCOUS FAN CLUTCH REMOVAL - INSTALL PROCEDURE
Use the procedure to remove the windhield washer and radiator overflow tank outlined above. Then remove the mehcanical fan as described above using the Crescent wrench. Once you get the fan and clutch assembly out of the engine compartment, you can remove the four bolts holding the fan blades to the clutch housing. I was not aware of any alignment marks for balance on this assembly. Just make sure you put the front of the blades on facing in the opposite direction of the nut on the back of the clutch housing. I didn't pay that much attention to this enough to give a more detailed procedure with bolt sizes, etc. This is pretty straight forward. Just put both clutch housings down on the floor next to each other before you remove the fan blades, remove the four bolts, move the fan blades to the new clutch housing and install the four bolts again. To put the assembly back on the water pump pulley shaft, just start the large nut on the threads and then spin the fan blades clockwise until they are as tight as they will go by hand. Then take the Crescent wrench, put it back on that nut in between the larger openings between the baldes and give it a good whack or two with a hammer in the direction of the dirver's side of the engine compartment to put it back on good enough.
RADIATOR
There are some posts in this thread by others on the type and quality of radiators that are on these Dakotas. I have not yet taken this defective one apart yet to see what clogged inside, but know it was clogged by something at the top and partially at the bottom, maybe in the middle too. In any event, my water pump was not pumping well enough because of a slipping fan belt that was too old and worn out to drive it properly. Don't know if this contributed to the eventual progressive clogging of my radiator, or if the acidic coolant environment explained in this thread by others was a simultaneous deteriorationg over time congruent with the belt situation. In any event, the radiator was bad as suggested by Dally and Allan. I chose to use the Dodge replacement radiator that came with my truck. It is the heavy duty radiator. Reason I used it is because all fittings should be in the same place as the original that was on my truck. I hate it when a replacment part has an out of place hole or fitting when I am half way through the job, so I get original equipment usually. Might cost more, but I'm doing the labor anyway.
RADIATOR REMOVAL - INSTALL PROCEDURE
I already had the windshield washer tank and radiator overflow tank removed and place on the right-hand side (driver's side) of the engine compartment, and had the mechanical fan and clutch removed as well as the belt to replace the belt tensioner assembly. So, the next thing to remove is the electric fan and lower fan housing. To do this it is best to remove the lower air dam under the front bumper that has the oil filter cap replacment hole in it. This is the hardest thing to do in my opinion because of those damn plastic retainers use to secure the plastic covers. They are just a mess to remove in my opinion and wish they were replaced with some kind of a large threaded plastic screw. When you get this off you have better unrestricted access to the bottom of the front engine compartment. There are three screws holding the electric fan housing to the radiator core housing. They are 10mm bolts. There are two more 10mm bolts holding the lower fan housing shroud on. There is an electrical connector that routes power to the electric fan. You disconnect this electrical connector by pushing the red locking slide in the direction of from the thin side of the red slide toward the thicker side. This unlocks the connector to the point where it will just pull apart easily. Then take the two screws out of the lower fan shroud so you can get the pigtail from the electric fan out from under the shroud through the slot for the wires in the bottom middle of the lower fan shroud. Then get back up and take out the three 10mm bolts for the electric fan housing and lift the fan out of the engine compartment. Then pull the lower fan shroud out of the engine compartment. Now you have a lot exposed, but you are still only half way done "exposing" things. I took the structuraly support rod that has 13mm bolts at the top middle holding it to the frame crossmember along the top of the radiator, which also has the hood latch on it, off next. There are also two more bolts at the bottom of the support rod where they terminate on the other end of their 45 degree angle downward. The 13mm bolt on the driver's side was easier to access from underneath the truck, the 13mm bolt on the passenger side was easier to access from the top of the engine compartment. Once you have these four 13mm bolts removed, the support rod can be worked out of the engine compartment by taking the passenger side downward enough to get the driver's side free to bring up and out. There are two 10mm bolts holding the secondary transmission fluid heat exchanger in the radiator housing in front of the A/C condenser, and there are two 10mm bolts holding the A/C condenser onto the radiator housing. These four bolts also have the Torx type of screw driver heads too, which came in handy for me because they are a bitch to access and remove the way I did it. I got two of them removed by accessing from below the bumper and two from in front of the bumper. The A/C condenser is also held in place by two supports that are slipped into two retainers on the radiator housing on each side about a 1/3rd of the way down from the top of the radiator in the front. There are two tube fittings on the passenger side and backside of the radiator that run to the transmission fluid heat exchanger. You have to remove these two tube fittings, and when you do some transmission fluid, probably less than an ounce, will ooze out into your catch pan. Then there is another 7mm BITCH of a bolt that holds a support strap on the bottom tubing to the transmission fluid cooling heat exchanger. This little bolt is on the bottom left, passenger side, backside of the radiator and the bolt head faces the left side of the vehicle. It is easier to get this bolt out and replace it once you have the radiator ready to lift out. Just remember it is there and has to come off to get the radiator out. The radiator drain is on the driver's side of the radiator at the bottom corner. You can drain the radiator by removing the drain tube from its uppermost connection, which is just there to keep the tube secured in place so it does not get debris into it, and letting the tube extend down beyond the bumper, which it doesn't. So, you need a splice of tube to lengthen it if you want to have the coolant go directly into your catch tank or tub. I jury rigged some Tygon tubing onto it using a syringe needle housing with a hole drilled in one end as the connector between the two tubes. Then open the drain valve by turning it counterclockwise. You may need a pair of pliers to turn it. I did. You can remove the radiator cap to allow the radiator to drain faster. Once you do that you can remove the two radiator hose connections from the radiator on both sides by using a channel lock pliers to grip the hose clamps to move them down on the hoses away from the radiator hose ports. It is good to have your catch basin or pan below to catch the radiator fluid that will be in the passenger side tube. You can bend it down to dump out the standpipe of coolant in it. Now you have to remove the main frame structure member above the radiator core. Before you do this remove the two 10mm bolts that hold the radiator to this cross frame member in the the two rubber mount isolations. I also had to remove two of those plastic retainers holding the rubber sheet on the left-hand front side of the radiator by that rubber mounting bracket. Then there are six 13mm bolts holding this cross member in place, that also has the hood latch mounted on it. Once you have these six bolts removed, use a screwdriver to pry the cross member out of both sides from the back side and below where it sits in its channel. It will pop right out and you can lay it up by the windshield washer/radiator overflow tank out of the way. Now the radiator is free except for that 7mm bolt at the bottom left and behind holding that tube retainer strap. Pull the A/C condenser up and out of the two slide down retainers on the radiator frame adn have your wife or helper hold that condenser and transmission fluid heat exchanger away from the radiator core. You can free the radiator by lifting it up and over toward the driver's side to get to that 7mm bolt. You will have to move the two transmission fluid heat exchanger tubes out of the way and move the radiator toward the driver's side to get it around the hose on the left hand side of the radiator. The radiator should come out completely now. Before you go putting the new radiator back in, make sure and check to see if all the nuts and retainer clips are on the new radiator housing. The new housing I had was missing two of those snap-in-place retainer nuts for the lower fan housing shroud, so I used the old ones off the bad radiator to fill in where they were missing on the new radiator housing. Clean things up a little with some paper towels or rags and then install the new radiator going just backwards in these instructions. Just make sure you put that little 7mm bolt holding the tubing support brace back no before you put the radiator completely back in place or you will have a BITCH of a time trying to get it on after you have the radiator secured in place. After you get it all back together, fill the coolant tanks again, and add some ATF (automatic transmission fluid) to your ATF dip stick tube. Add about as much as you figured you lost when you took those two fitting off the back of the radiator that go to the transmission fluid heat exchanger. You can always check your transmission fluid level when you get the tranny back up to operating temperature and add more then if needed. Proably better to just add it as needed after you check it at temperature. You might check the two fittings for tightness on the transmission fluid heat exchanger when you get done. Make sure you fill the overflow coolant tank again per owner's manual.
Radiator cap and hoses should be checked as they can be defective too. Others here have had experience with radiator caps. I've never had one go bad on me yet, but then again, I never had a bad radiator ever on any of my vehicles in over 40 years of driving. This was the first one for me.
Biggest problem I have had with two of my Dodge vehicles is the brakes. Absolutely horrible brakes (warping discs every 12-15K) on my Dakota and Stratus, but not on my Durango or Caravan.
Caravan had phantom windshield wipers that would come on anytime unexpectedly and started to have tranny quirks or shift linkage problems over 80,000 miles where it would not get into gear. Both Durango and Dakota had bad ball joints on them from factory and were replaced under warranty. All four vehicles had wheels out alignment off the dealer's lots.
First place I alway hit right after I buy a Dodge is a wheel alignment shop. Stratus had a bad computer setup and ran overly rich fowling up the engine with carbon so bad it messed up the valve seats earlier than usual. Other than that, I'd never buy a Ford every again. They had even more problems than my Dodges. The five Toyotas I had over the years were the least plagued with mechanical problems of all my vehicles.
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varnuke
Dodge Dakota
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10/12/2003
21:49:58
| RE: 4.7liter Overheating - Case History
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I've got pictures of the core that show why it is blocked. If anybody wants them, let me know and I'll forward them to you.
There is a buildup of deposits on the outlet side of the radiator, like calcium deposits or something from the antifreeze/aluminum reaction or just some kind of a crystallization from the chemicals, heat, and flow, I am guessing.
This is my fault for not doing periodic maintenence on the coolant system like suggested by others already. So, what is there is a buildup of deposits in a system that was run without changing or flushing for three years, or from March 2000 until now.
I am sure that there is something that can dissolve this stuff, as it reminds me of kidney stones. Who knows, maybe even ultrasound shot in from the end of the radiator may be enough to bust it up enough back to a microscopic colloid particle at least. The core is fine otherwise. There is no noticeable corrosion in it at all and the inlet side is as clean as it can be.
Because of this I suspect that the radiator got bad faster than it would have if my pump was constantly putting out a good solid flow rate.
I think Dally's suggestion of adding a neutralizer may be what is needed to stop or hinder the chemical reaction that is causing this buildup. Did you have a brand name on this "neutralizer" stuff you mentioned Dally?
I know in our boilers we added Trisodium Phosphate (TSP) and Disodium something or other, can't remember, to keep the pH up in the 10-11 range. Not sure if adding TSP is the way to go here on this one. Need to search for these answers now. Once I can identify a substance that can dissolve this stuff, it would be pretty easy to save a radiator in the condition mine was in because the structural part of the core, etc., was in perfect condition. These deposits did not eat away at the aluminum, only built up to the point where they eventually blocked the narrow passageways.
If you could get the plastic plenums off easily enough without ruining the tabs that hold them on, there is no reason why these cores could not be cleaned with a "rod" and put back together. The moist buildup can be easily removed with a finger rubbing it, and I suspect that the coolant channels could be blown out with air and cleaned that way too.
I'm going to do some experimenting on what is there as time permits. Right now it is drying out which will probably make it harder to remove. That will be better if I can find somethnig that dissolves it from that condition easily enough.
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Jay
Dodge Dakota
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10/12/2003
22:47:46
| RE: 4.7liter Overheating - Case History
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varnuke--
Thanks for the comprehensive lesson. I'll copy it out and file it in my Dodge Dakota repair book.
-- Jay
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Allan
Dodge Dakota
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10/13/2003
12:46:58
| RE: 4.7liter Overheating - Case History
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Varnuke,
I am glad that you have finally got it all done. I'm wondering if you had replaced the radiator in the first place then that would have been the only work that would have needed to be done. I remember having the radiator changed on my GT Mustang costing around $250 about four years ago. Could you let us know the cost of the radiator from the dealer. Did you buy the core or the assembled radiator. On the Mustang they replaced the core only and used my plastic end peices.(what ever they call them). Still don't think it is cost effective or reliable to rod out an aluminium core. Was your original pump leaking or did you think that the impellor was spinning on the shaft? When you look back, it seems to me that all that needed to be done was to replace the radiator. The only reason that they say to replace the belt at 60,000 miles (or so) is that they are cautious of it breaking not wearing out.Belt tensioners don't wear out. I have seen one break apart on my exes Caravan but that is all. Should last forever. Anyway glad it is up and running.
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varnuke
Dodge Dakota
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10/13/2003
15:21:44
| RE: 4.7liter Overheating - Case History
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Allan, the initial problem with overheating was due to the backside of the belt being too worn out, or like I said in one of the above posts, it was as smooth as a sheet of glass. The new belt has a good sticky rubber surface that presents a better friction coefficient to the water pump pulley.
When I look back on the whole scenario, what initially was going on was the water pump was not being driven constantly except maybe at highway speeds. When I would slow down and the mechanical fan would kick in, that would present more torque which would cause the belt to slip on the water pump pulley, and thus, the pump would not rotate as fast, less flow rate, and I think more buildup of that soft crud on the effluent side of the core and in the coolant channels. The water pump impeller was in perfect condition and secured to the shaft well. There was no visible problem with the water pump, but the bearings were a potential problem area as always.
After I got to replacing things, one by one, starting on the wrong end [which turned out to probably be the best end to start with in retrospect for my actual problems] with the least likely things to be causing the actual problem, I did eventually find that the bearings on the water pump were just starting to deteriorate to the point where there was some play between the shaft and housing that you could sense when spinning the pulley as fast as possible by hand, but they were not bad enough to cause the pump to fail anytime soon. Spinning the old pulley and comparing it to the spinning of the new pulley showed a clear differnce in "tightness" of the bearings. The thermostats were all good, and the fan clutch was still good, but clogged with bugs, dirt, grit and oil in the bimetallic strip on the front that activates the clutch mechanism.
If I had started with the radiator first, I might have overlooked the fan belt/pulley problem. What the slick fan belt did to the water pump pulley was is wear all the black paint off of the pulley down to the bare metal, and polished it to a good enough finish for an O-ring sealing surface.
After showing it to the service manager and another German shop guy up the street this morning, the first question asked was if the coolant was the red stuff from Chrysler. I think it was but can't remember now. The service manager said even so it supposedly should not do what it had done to my core for at least five years.
There is some kind of a chemical jelling/plating action going on with that red antifreeze it seems. The gunk it creates is somewhat off white or beige in color and grainy like little pieces of grit or sand, kind of like a pasty substance that you can rub off with your finger easily enough when wet, which is why I figured that the decrease in flow rate actually helped accelerate the percipitate clogging problem.
The core of the radiator is in perfect condition as far as any corrosion of the metal is concerned. When you take and bend the little metal fingers back that hold the two plastic plenums onto the radiator core, you have essentially ruined them and the core. I have not looked at it close enough to see if those metal tabs or fingers can be replaced or not, but I would suspect that you need a special fixture and press to get those plenums back onto the core properly aligned so the rubber gasket is in place and seals properly. I would not try to put those plenums back on now the way I took it apart.
I am quite certain that this crud could have been flushed out of my radiator, to make it just like new, if I could identify what it is that breaks it down or loosens it up enough to be flushed out with a reverse flow through the radiator. If I could have gotten a small nozzle down in front of each cross tube in the core and shot a pressurized stream of water/cleaning solution in them, I'm sure it could have been cleaned out completely. It is the little grains that act like platelets and slowly coagulate kind of like blood when the flow rate decreases, the way I see it.
The Serpentine belt was not cracking on the ribbed side anywhere. The only problem with it was the slick backside that drives the water pump pulley. You have to remember that I put about 150K on this truck in about 2.5 years, so the materials themselves [rubber] did not yet start to break down because of age, but rather because of mechanical wear mainly.
The radiator, heavy duty with tranny cooler, was $305 with tax. The belt tensioner was $90. My tensioner was sticking at one point along its radial movement.
The way I look at it now, I have the old green antifreeze in there, new everything associated with the coolant system, and it seems to be working just like it did when brand new. Yeah, I spent $600 on parts, the labor was proabably 15-20 hours overall since I started replacing things, and I'm sure it would have cost me at least $1000 to have had it all done by a shop somewhere, maybe more.
Doing it yourself you know it is done without someone stripping a bolt in a component somewhere and not giving a you-know-what about it, etc. I had the first thermostat replaced at a Dodge dealer in town and whoever did the job ruined the 8mm bolt heads on the two bolts that hold on the thermostat housing. I had to go up to Sears and get their damaged bolt head extractor set to get them out. From that point on, I figured that I was going to do the rest of the work on it from now on, as long as I have the necessary tools to do everything myself.
My very next project is to replace the back shocks, and then figure out how to check the front end ball joints to make sure they are good and replace the front shocks. The ball joints were replaced within 12,000 miles under warranty because they were apparently bad from the plant.
Then I have that door lock solenoid or something that squeals like a wounded rabbit when I use the electric door lock switch. I'd rather do the radiator again than take off the inside door panel. Hate working with the asthetic stuff on the inside of the passenger compartment.
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Allan
Dodge Dakota
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10/14/2003
08:18:05
| RE: 4.7liter Overheating - Case History
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This has certainly been a long process for you to go through but it's great that we all get to learn something from each others problems. The important thing is that it's fixed and we were able to see the process you went through. All good in the end.
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varnuke
Dodge Dakota
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10/14/2003
11:56:48
| RE: 4.7liter Overheating - Case History
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The first place I went to look for information on this type of problem was the internet, and I found this site and forum.
I spent some time looking through it for some detailed information on what could be the problem with my machine, which was the start of my learning process with the coolant system on my truck.
This is why I have taken the time to post a comprehensive summary with detailed procedures back on this website. There may be a couple of different ways to appraoch the actual disassembly/assembly, but at least what I have written gives someone an overall view of what he will be getting into before starting a repair on something he too may be doing for the first time.
It was suggested earlier in one post that my approach was a "shotgun approach" to the problem. That was an interesting comment to me, in that it indicated how important it is to read and get familiar with all of the information posted in any particular thread before posting something.
The start of my post only dealt with the coolant system. Then Jay introduced an additional factor, concerning his oil pressure [which still has me stumped, but am thinking it is an electrical signal problem at this time; hope he hunts the problem down and lets us know what it was]. Then another person appeared to get my problem directly associated with Jay's problem, when I had no oil problem component to my situation.
I hope more people take the time to write up more detailed instructions on how to repair the problems they encounter on anything they do themselves. It is kind of like the see one, do one, teach one, approach. If I can read about it up front, then I can "see" what has to be done, which gives me more confidence in being able to do it myself, knowing what I am getting into prior to actually starting the task. I'd like to see a detailed procedure for repairing that "rabbit squealing" door lock on the driver's side. One that is precise on removing the door panel to get to it. That interior stuff bugs me.
I hope what I have written comes in handy for others, and maybe even saves them money by not having to take a "shotgun approach" to their overheating problem when it appears.
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varnuke
Dodge Dakota
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10/14/2003
20:01:18
| RE: 4.7liter Overheating - Case History
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Found this, and think it applies to my case, at:
http://www.frontierequip.com/service/lowsilicate.htm
Many people think that all cooling system antifreeze products are the same, except some are methanol based and some are glycol based. Not so! In newer automotive applications, silicates are needed to protect aluminum engine parts and radiators from corrosion, and are used in virtually all antifreeze mixtures in varying forms and amounts.
Eventually, silicates are supposed to drop out of the coolant mix, and as long as they do so at a controlled rate, they work quite well. However, over time, the "soup" of chemicals, impurities, and corrosion by-products in a cooling system can start to behave in ways difficult to analyze or predict. When silicates begin to drop out too rapidly, they build up and form a gel.
A number of things can start this process: high silicate levels from incorrect antifreeze concentrations or improper use of coolant additives, impurities in very hard water, and severe engine temperature swings.
The main effects of the formation of this silicate gel are clogging of radiator and heater cores, and engine overheating. Silicate gel buildup greatly reduces heat transfer from the engine castings to the coolant. When the gel coats the temperature sender, engine overheating can take place without notice. Silicate gel also carriers abrasive particles to the water pump, where it wears away pump seals causing leakage and failure.
Unfortunately, there are few effective methods for cleaning the gel from an already-clogged system. Radiators must be removed and sent out for a thorough cleaning. The engine must be flushed with a caustic solution. The gel is not water soluble, so flushing with water alone will not work.
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varnuke
Dodge Dakota
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10/14/2003
20:14:28
| RE: 4.7liter Overheating - Case History
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Found another one at:
http://usapc.army.mil/messages/tav105.htm
SUBJECT: TECHNICAL ADVISORY MESSAGE #105, USE OF ALTERNATIVE
CLEANING COMPOUND FOR MILITARY VEHICLES' COOLING SYSTEM
1. MIL-C-10597 ENGINE COOLING SYSTEM CLEANING COMPOUND HAS BEEN CANCELLED BECAUSE OF ITS TOXICITY TO HUMANS. FLEET GUARD'S "RESTORE" AND "RESTORE PLUS" CAN BE USED AS AN ALTERNATIVE FOR CLEANING MILITARY VEHICLE COOLING SYSTEMS. A TANK-AUTOMOTIVE RESEARCH, DEVELOPMENT AND ENGINEERING CENTER (TARDEC) STUDY, CONDUCTED BY SOUTHWEST RESEARCH INSTITUTE, FOUND THAT THE COMMERCIALLY AVAILABLE CLEANING PRODUCTS, "RESTORE" AND "RESTORE PLUS" ARE EQUIVALENT TO TO MIL-C-10597 CLEANER AND LESS HAZARDOUS TO MAINTENANCE PERSONNEL. HOWEVER, THE USE OF COOLING CLEANING COMPOUND AS A ROUTINE MAINTENANCE PROCEDURE, I.E., EACH TIME ANTIFREEZE IS ADDED OR DRAINED FROM THE COOLING SYSTEM, IS NOT RECOMMENDED. THE COMPOUND SHALL ONLY BE USED WHEN NECESSARY TO CLEAN HEAVILY RUSTED OR PARTIALLY CLOGGED COOLING SYSTEMS. FOLLOW TM-750-254 SECTION 2-33 FOR MORE INFORMATION.
2. "RESTORE" IS AN ALKALINE-BASED CLEANER EFFECTIVE FOR CLEANING SILICATE GEL, OIL CONTAMINATION AND SOLDER BLOOM. IT IS NOT AN
EFFECTIVE TREATMENT FOR HEAVY RUST AND SCALE DEPOSIT. "RESTORE PLUS" IS AN ACID-BASED CLEANER AND IS EFFECTIVE IN REMOVING SCALE, OIL, AND FUEL FOULING. IT DOES NOT REMOVE SILICATE GELATION. BOTH OF THESE PRODUCTS MUST BE USED TO REMOVE ALL CORROSION, SCALE, AND DEPOSITS CLOGGING THE RADIATOR. USE EACH CLEANER SEPARATELY AND DO NOT MIX. EACH CONTAINER IS PACKAGED WITH INSTRUCTION PAPERS PROVIDED BY FLEETGUARD. WHEN USING "RESTORE" AND "RESTORE PLUS" FOLLOW THE MANUFACTURER'S INSTRUCTIONS FOUND ON THE LABEL OF THE CONTAINER.
3. TO DETERMINE HOW BADLY A RADIATOR IS CLOGGED WITHOUT REMOVING IT FROM THE MOTOR VEHICLE, TEST IT WITH A FLOW TESTER. A FLOW TESTER INDICATES THE EXACT AMOUNT OF GALLONS OF WATER PER MINUTE THAT WILL FLOW BY GRAVITY THROUGH THE RADIATOR. CHECKING THIS READING AGAINST THE FLOW RATE OF A NEW RADIATOR WILL INDICATE THE EXTENT OF CLOGGING. (THIS PARAGRAPH IS TAKEN FROM SECTION 3.7 OF THE TM-750-254.) ONCE AGAIN, IT IS IMPORTANT NOT TO MIX THE TWO CLEANERS TO ACCOMPLISH THE CLEANING TASKS.
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Cherie
Dodge Dakota
JOIN HERE
5/24/2004
09:03:00
|  RE: 4.7liter Overheating - Case History
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I have a 2001 Dakota. I seem to have a problem only in heat of the day and when I climb hills. We have just changed the thremostat and pressure cap on radiator. I don't know what is wrong. Very frustrated at this time. Plan to go to dealership after work today and hoping they can find the problem. I am open to any suggestions and HELP!!!!!!.
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Jim H.
Dodge Dakota
JOIN HERE
7/28/2005
00:32:57
|  RE: 4.7liter Overheating - Case History
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Well Fellas,
Newbie to this site and what a great site it is. Varnuke was correct in saying to replace the radiator first. I didn't replace quite as much stuff as he did, but, after the pressure flush from the dealer who stated the rad was working fine, along with the waterpump, not to mention the belt looking fine, I still had the temp increase when pulling a slight hill, with the A/C on. I ran it up to 235-240 degrees before switching the heater on to cool the engine. Not the best thing to do. If you are having similar problems, I suggest you use an "infrared thermometer" on your rad. Mine read 190 near the filler and at top hose at the engine, 175 on the left side, and only 130 in the middle !!! Remember, dealer told me it was fine only 6 weeks prior!!! Sure water was moving but there was no pressure when removing the cap and that's not a good thing !!! Forget the belt, tensioner pulley, and all the other crap posted here on this issue and replace the rad first !!! It will save you time and a lot of headache. These rads need a complete flush every year to get the life out of them. Also, when filling or topping off with water, make sure it is "distilled water."
2000 Dak 4.7 Ext Cab 4x4 Dodge piece of Sh!#*%
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Kowalski
GenIII
7/28/2005
13:58:25
| RE: 4.7liter Overheating - Case History
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Jim - I wouldn't advocate replacing the radiator first unless it was tested and found to be the problem. Its not unusual for a faulty thermostat or radiator cap to be the problem. When using the "shotgun" aproach to mechanincs (not the best aproach) the least you can do is to try replacing the cheapest parts first. The diagnostic aproach is preferred. Just because this is what solved the problem for you doesn't mean it will be the same for everybody.
Lead, follow, or get out of the way
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Jim H.
Dodge Dakota
JOIN HERE
7/29/2005
02:50:37
| RE: 4.7liter Overheating - Case History
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I guess it would be best to have it tested first to the tune of $50 or so. For the same amount of $$$ you can get an infrared thermometer from Costo and test it yourself. Not only that, but you'll have a nice new tool to put in your toolbox. The way the shop that replaced my rad tested the old unit was to stand the rad on end, shoot water into it and watch how fast and how much volume shot out the lower port. They did this to double-check the infrared reading. Needless to say, I didn't buy a new water pump, tensioner pulley or serpentine belt, just a rad and it solved "MY" overheating problem. It appears that this proceedure has solved quite a few other's overheating problems too! Shotguns are my friend.
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chris
Dodge Dakota
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8/16/2005
00:02:46
| RE: 4.7liter Overheating - Case History
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I have also replaced my radiator cap and thermostat. Does any one know any good web sites to find an oversize rad, and will they fit in my dak. I have a 4.7, 01 dakota. Any info would be greatly appreciated.
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Jim H.
Dodge Dakota
JOIN HERE
8/16/2005
10:43:33
| RE: 4.7liter Overheating - Case History
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Chris,
Try www.jegs.com or www.summitracing.com.......
Also, try www.1aauto.com. Chances are the first two sites would be more likely to have oversized rads for cooling issues.
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Marcus Bowens
Dodge Dakota
JOIN HERE
8/08/2006
20:56:13
| RE: 4.7liter Overheating - Case History
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Check you radiator dimensions if you dak has max cooling the radiator should be 1.5" thick if it was like mine it was only 15/16" thick. I put the larger radiator in mine and it runs cooler now
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