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KahunaGrande
Dodge Dakota
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6/12/2005
13:14:17
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 Subject: '99 5.2 still overheating
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Message:
Burped the cooling system 3 times and thought I had it licked but after a quick test drive it still marches up to PFH (Pretty F'ing Hot).
Here is what I have done:
New Prestone GenII 180-189 T-stat (I drilled 1/8" burp hole) and gasket
New 16# pressure relief cap
New upper hose
New bypass hose
New intake gaskets
New intake plenum gasket (the cause of this whole adventure)
I checked belt orientation I(it's good)
I burped the system (3 times)
Symptoms are:
It warms up very slowly to about 210, then quickly heats up to PFH (see above).
The upper hose gets very hard but there is not enough system pressure to crack the 16# cap. I can feel and hear boiling in the hose whenever it is above about 210.
At idle it will work back down to around 210, and will go lower with the heater blasting. Just does not seem able to cool under a load once the temp goes above 210. Ambient air temp this morning was mid 60's.
I am fixing to do the following:
Remove t-stat and reassemble, see if it works better with no t-stat
Drain it (again) and put in a Prestone flush kit
Backflush the system
Reassemble with either a stock temp range t-stat (Prestone GenII 190-199) or the GenII 180-189
Any bright ideas about what could cause it? Anything else I should check?
Arrrgh!!!!
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Rob C
Dodge Dakota
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6/12/2005
13:40:29
| RE: '99 5.2 still overheating
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Remove t-stat, put in pot of water and heat up (on stove), make sure the t-stat opens before the water boils (212 degree F). Check to see if you have areas on you engine/heads that are much hotter than rest of engine (you'll need a thermometer designed for this). It sounds like you aren't flowing coolant through the radiator. When you changed your manifold gasket, did you make sure the gasket wasn't blocking any water passage? Also, did you stuff anything into the water passage and intake ports while you were scraping the old gasket off and left those stuffings in by accident?
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KahunaGrande
Dodge Dakota
JOIN HERE
6/12/2005
16:47:02
| RE: '99 5.2 still overheating
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Message:
OK,
Good questions. We checked the water passages because I had heard the intake gaskets were left and right handed but they were not marked so we checked them against the heads when we put them on.
I used big red shop rags to protect the big openings and we did account for them.
I pulled the new 180 t-stat and reassembled the truck without it and it is running fine. I drove it around both intown and near highway speeds. Ambient temp is mid 70's - with the A\C on and idling, after a run to 55-60mph, the side of the needle never touched the 2 in 210. Looks like it is staying between 140-180 with no t-stat.
I have a 2000 mile trip coming up this week and am considering running it without the t-stat installed. Route is NM, TX, OK, KS, MO. Other than warming up a little slower should I expect any other issues?
Thanks in advance
John
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Rob C
Dodge Dakota
JOIN HERE
6/12/2005
18:57:16
|  RE: '99 5.2 still overheating
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Message:
Yes, running without a thermostat is not a good idea at all. Your engine needs to be at 180 degrees minimum. Most oils are engineered to run above that temperature, especially petroleum based oil. If you run your engine at too low of a temperature for extended periods can cause a significant increase in the wear of engine parts. Also, you'll most likely get decreased fuel economy and I'm surprised that you aren't throwing a code P0125 'Engine is Cold Too Long'.
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KahunaGrande
Dodge Dakota
JOIN HERE
6/12/2005
22:09:54
| RE: '99 5.2 still overheating
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Message:
Thanks Rob C,
I am not getting any codes with the key and trip\reset method on the odometer, and I don't have an OBD scanner.
I am running full synthetic oil (have been for last ~20,000 miles).
After I removed it and thought about setting off on my trip without a t-stat, I put the 180 in a pan of water and heated it up, it did not open, so maybe it was just a bad unit. I took it up to 200 degrees and left it for several minutes, no dice.
I am going to test the stock temp range t-stat before I install it but it looks like it was just a lemon t-stat.
Go figure.
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daddio
Dodge Dakota
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6/13/2005
11:22:41
| RE: '99 5.2 still overheating
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Message:
how about the waterpump? or try another t/stat but test it before installing it.
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Mason
Dodge Dakota
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6/13/2005
13:50:45
| RE: '99 5.2 still overheating
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Message:
Could be something as simple as the radiator cap being incorrect, or just bad.
Cheap fix.
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Rob C
Dodge Dakota
JOIN HERE
6/13/2005
19:30:03
|  RE: '99 5.2 still overheating
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Message:
I'd get another 180 t-stat and test it. If it works in the pot of hot water, drill the bleed hole and install it.
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