Milky coating inside cooling system???

Subject: Milky coating inside cooling system???
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My 01 4.7 (recently purchased with 90K miles) was running a little hot when towing 1000# or climbing grades, but not boiling over or overheating. I decided to flush out the cooling system, install a 180 degree thermostat, new cap and replace the coolant.

I dumped the coolant and noticed it was the ol' green stuff. I thought to myself, this isn't HOAT coolant, all though it looked in good condition. When I popped off the thermostat housing I noticed a chalky film of white sludge covering the inside of the housing. It took some light scrubbing with a towel and water to remove the film, but now I'm trying to figure out how to get the film off the inside of the radiator and engine cooling passages. I'm guessing the film is causing poor heat transfer in the engine and radiator.

Have a few questions,,,

- Is HOAT antifreeze (Zerex G05) the correct coolant for a 2001 4.7?

- What causes the chalky white film or sludge (I don't think it's oil as the engine hasn't had problems and the substance is not oily. Mixing coolants, HOAT and old green stuff? Too many miles on coolant?

- What's the BEST radiator flush that will get rid of the chalky feeling film?

- Will flushing get rid of the chalky film or is it new radiator time?

After flushing, changing the coolant, 180 degree thermostat and rad cap, it does not seem to run as hot pulling grades or towing 1000#, but I have a sneeking suspicion when I hook up my 3500# boat it's going to overheat.

Suggestoins?

Marv
Dodge Dakota
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8/26/2007
17:19:35

RE: Milky coating inside cooling system???
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"Is HOAT antifreeze (Zerex G05) the correct coolant for a 2001 4.7?"
Yes.

Keep an eye on the overflow reservoir level for a while, as the rest of the air purges from the system.

SteveJ
Dodge Dakota
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8/26/2007
17:54:43

RE: Milky coating inside cooling system???
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A few extracts from my 2004 Service Manual about coolant for the 4.7L:

“
CAUTION: Mopar Antifreeze/Coolant, 5 Year/100,000 Mile Formula (MS-9769) may not be mixed with any other type of antifreeze. Mixing of coolants other than specified (non-HOAT or other HOAT), may result in engine damage that may not be covered under the new vehicle warranty, and decreased corrosion protection.

COOLANT PERFORMANCE
The required ethylene-glycol (antifreeze) and water mixture depends upon climate and vehicle operating conditions. The coolant performance of various mixtures follows:

Pure Water - Water can absorb more heat than a mixture of water and ethylene-glycol. This is for purpose of heat transfer only. Water also freezes at a higher temperature and allows corrosion.

100 percent Ethylene-Glycol - The corrosion inhibiting additives in ethylene-glycol need the presence of water to dissolve. Without water, additives form deposits in system. These act as insulation causing temperature to rise to as high as 149°C (300°F). This temperature is hot enough to melt plastic and soften solder. The increased temperature can result in engine detonation. In addition, 100 percent ethylene-glycol freezes at -22°C (-8°F).

50/50 Ethylene-Glycol and Water - Is the recommended mixture, it provides protection against freezing to -37°C (-34°F). The antifreeze concentration must always be a minimum of 44 percent, yearround in all climates. If percentage is lower, engine parts may be eroded by cavitation. Maximum protection against freezing is provided with a 68 percent antifreeze concentration, which prevents freezing down to -67.7°C (-90°F). A higher percentage will freeze at a warmer temperature. Also, a higher percentage of antifreeze can cause the engine to overheat because specific heat of antifreeze is lower than that of water.

NOTE: Refer to the vehicle’s coolant bottle to identify HOAT or Non-HOAT coolant. Non-HOAT coolant is green in color.

The use of aluminum cylinder blocks, cylinder heads and water pumps requires special corrosion protection. Only Mopar Antifreeze/Coolant, 5 Year/100,000 Mile Formula (glycol base coolant with corrosion inhibitors called HOAT, for Hybrid Organic Additive Technology) is recommended. This coolant offers the best engine cooling without corrosion when mixed with 50% distilled water to obtain to obtain a freeze point of -37°C (-35°F).
”

Also, never use tap water to mix with the coolant. Tap water contains chemicals and imputiries that may react with some cooling system components over time, and cause corrosion. Always use distilled water.

DSW
Dodge Dakota
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8/27/2007
15:33:18

RE: Milky coating inside cooling system???
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After finding non-HOAT antifreeze and chalky stuff in the cooling system I flushed it with the garden hose until it ran clear. I dumped 1/2 gallon of Simple Green into the radiator and ran the engine for an hour, 1/2 idling, 1/2 driving. Some of the chalky stuff did come out, but I fear there is a good layer still in the system.

BTW, Even though the Simple Green seemed to get some of the stuff out, I don't suggest flushing with Simple Green as it took almost an hour to get it out of the system, for the water to run clear and non-foamy. Royal PITA!

After getting all the Simple Green out of the cooling system I emptied the radiator and filled it with distiled water, then slowly dumped 6 gallons of distilled water into the radiator which purged most of the tap water. I had a funnel and hose stuck down into the rad hose so the pure water was going into the radiator and old hot tap water was coming out of the filler neck. I drained the rad again and filled it with HOAT antifreeze,,, and again with the funnel and hose dumped another 3/4 gallon of HOAT into the cooling syste, 50-50 mix.

For the next 1/2 hour I left the cap off while the system burped itself. I also flushed the overflow tank and filled it with 50% distilled water and 50% HOAT. While the system was burping itself I could see small flecks of the white chalky stuff floating in the water.

Since I know the chalky stuff is still in the cooling system I want to dump something into the cooling system to get rid it, but don't know what will get rid of the chalky residue without damaging the cooling system. I know of something that will disolve the chalky stuff, but it will also disolve the aluminum radiator and other aluminum parts,,, so I'm not going there... LOL

Any suggestions on a good radiator flush that will dissolve the chalky residue?

wtf
Dodge Dakota
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8/28/2007
08:01:53

RE: Milky coating inside cooling system???
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why the hell would you put "simple green" into the cooling system????
try something made for the purpose
prestone and zerex both make a good super flush

http://www.prestone.com/products/coolingSystemTreatments.php

http://www.amazon.com/Prestone-AS107-Super-Flush-oz/dp/B000BPSVWI

http://www.valvoline.com/pages/products/product_detail.asp?product=16

Shoe
GenIII

8/28/2007
10:51:06

RE: Milky coating inside cooling system???
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We always used Cascade. That sh!t works the best.

Finally... a V8. '01 Dodge Dakota RC, 4.7, 5-speed, 3.92 LSD. = R/T Killer.
well at least a stock one

DSW
Dodge Dakota
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8/28/2007
14:44:47

RE: Milky coating inside cooling system???
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Thanks for the input guys,,, it's just what I was looking for...

I've used the Prestone and Zerex flushes before and didn't experience good results, weak, poor quality, consumer level product.

FYI, I know of a machine shop that uses 100% SIMPLE GREEN to hot tank engine blocks and heads. They use it because it's pretty safe on metals, works "almost" as well as their old caustic cleaning solution and they don't have as much of a hazardous waste problem to deal with.

Back to the question at hand, does anyone know of a good radiator flush (non-consumer grade) flush that will remove the chalky residue.

DSW
Dodge Dakota
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8/28/2007
16:18:51

RE: Milky coating inside cooling system???
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I finally found something other than the cheap OTC stuff. The procedure sounds a bit involved, but if it cleans up the cooling system it will be worth the effort. For all the nay-sayers out there, Mercedes uses citric acid to flushing their cooling systems.

To start with acquire 2.5 lbs of Citric acid. Food or lab grade doesn't matter. This can be acquired at many food suppliers online or ebay. I got mine at www.bulkfoods.com.

Now is a good time to locate your block mounted drain plug which will make each step of this far quicker.

Step #1 - You will need to drain and flush your cooling system to remove as much anti-freeze as possible before you start. You should flush at least three times with clear water. Running the car to operating temp each time and allowing it to cool enough to comfortably hold the lower radiator hose or the bottom of the radiator between flushes. Make sure your heater is set to run full blast (maximum temp setting) during each and every stage so the heater core is cleaned as well as the radiator, and the engine block.

Step #2 - You need a degreaser, preferably non-sudsing one. Shout will work as will some dishwasher detergents (properly dissolved in hot water completely first) or get Some Prestone radiator flush from the parts store. This will degrease however is too wimpy to do much more than that. How much is enough? I would use a 17 - 20 once container. Better to err or the side of too much than too little and not degrease the system enough. This is a critical step as the Citric acid will not do its job with any oil or lubricants from the antifreeze in the system. Since you are taking the time and expense to this then it would be best to do it properly. Mix the degreasing agent of your choice and fill the radiator full of water, and run the car at least 20 minutes after it is up to operating temp. It is easiest to do this with a short drive. Allow to cool down and flush several times until the water no longer feels slippery that you are draining. Three times should be enough.

Step #3 - Mix your citric acid (it’s a dry powder) with 1.5 gallons of hot tap water in a clean bucket or other container. When it’s been completely dissolved pour the mixture into your radiator and top off with tap water.

Take a drive....of about 30 to 60 minutes duration (with heater on maximum temp) after it is up to operating temperatures, you need to get a good vigorous circulation so idling in the driveway will not cut it.

I would avoid leaving this in the radiator for several days or even over night so try to do this step when you have the time to complete it, and the first couple following flushes within a few hours at most.

When the engine has cooled down drain it well, and refill with tap water run up to operating temp for a few minutes then drain when its has cooled off. You do really want to drain with the block plug removed as well as the radiator drain or removing the lower hose. Sediment or rust flakes will not exit the system via the radiator and trust me there will be a lot. You want to do this at least 3 times and until the water coming out does not have a greasy feel to it. This is very important. If you wish you could also do the next step and dissolve 1 lb or baking soda (sodium Bicarbonate) into a gallon of hot water and use this on your third flush. This will help neutralize any pockets of acid that may remain. If you do this step you still must flush at least 3 more times thoroughly.

Step #4 - Refill your cooling system with a 50/50 mix of antifreeze that is recommended for your vehicle and water.

This is time consuming and will take a weekend to complete....but you will only have to do this once...and it will be a better more thorough flush than any shop will achieve.

NOTE: As far as the fluids being drained, you need only be concerned about the initial draining of coolant. Please capture the initial drain and take it to an appropriate disposal center. All subsequent flushes are almost 100% water, water with a biodegradable degreaser, or water and citric acid and are safe to be drained straight to the ground.

Once I have finished the flushing procedure I'll post back as to how effective it is.

fairway551
Dodge Dakota
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9/07/2007
20:19:18

RE: Milky coating inside cooling system???
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What's the best/easiest way to drain the coolant system for a 2001 4.7L engine? I can't find the drain plug on the radiator.

DSW
Dodge Dakota
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9/10/2007
01:19:38

RE: Milky coating inside cooling system???
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The citric acid worked very well. The procedure took a long time and I could have done it in 6 hours. But,,, I decided to install new OEM hoses and the lower hose had a defect which leaked under pressure. Nothing like citric acid spewing all over the engine and under carrige, luckily it rinsed off easily.

When I dumped in the citric acid/water solution it was clear, but it came out looking like skim milk since there was so much cr@p built up in the cooling system. After flushing the citric acid with fresh water, I replaced the upper hose and it was as clean as a whistle. No more chalky coating in the hose and even the spring was perfectly clean.

I topped it off with antifreeze/distilled water and took it on a drive up to the mountains, 9000'. It stayed much cooler and never got close to getting hot, 1/2 way up on the gauge, 195-200 degrees with a 180 degree thermostat. On the same trip a few weeks ago it was riding up to 3/4 on the gauge instead of 1/2 it's running now.

For the question of draining the radiator on a 4.7, the drain plug in on the side of the radiator at the bottom, battery side of radiator.

P 1

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