Overheating

2008 DODGE CARAVAN
170,000 MILES • 3.3L • 6 CYL • 2WD • AUTOMATIC
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FANTASTICW
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The van started overheating after travelling most of the day in ninety five degree heat, we were using the A/C.
The radiator fan runs, there is coolant in the reserve bottle as well as the radiator. I flushed out the radiator, but the only thing that will help cool the engine is using the heater, (A/C off), full blast. there is noting coming out of the exhaust pipe to suggest a head gasket. I am thinking possibly thermostat, but I do not know how to check it.
Jul 13, 2017 at 4:49 PM
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STRAILER
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Hello,

The best way to check the thermostat is to replace it. Here is a guide that will show you what you are in for when doing the job:

https://www.2carpros.com/articles/replace-thermostat

and

https://www.2carpros.com/articles/engine-overheating-or-running-hot

Here is a diagram on how to do it on your car. (below)

Please let us know what happens.

Cheers, Ken
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Jul 14, 2017 at 11:54 AM
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FANTASTICW
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I replaced the thermostat, but it still over heated. I then back flushed the radiator, (a lot of brown colored water came out), and it has been running okay without the heater on. I can run the a/c, but I can see the gauge climb to close to 3/4 on the freeway.

Is it possible the radiator may still have some clogs in it and just needs to be replaced?
Jul 14, 2017 at 1:12 PM
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MHPAUTOS
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The radiator may have some blocked core tubes, a radiator repair shop can clean this out for you, the tanks need to be removed it is not something that you can do at home.
If it was neglected long enough for brown liquid to come out it may very well be clogged and need a "Rod-out" which requires disassembly of the radiator. New radiators are aluminum and plastic, so after so long they are not repairable and need to be replaced due to fatigue of the materials.

See the guides below for flushing your cooling system and replacing your radiator.

https://www.2carpros.com/articles/coolant-flush-and-refill-all-cars

https://www.2carpros.com/articles/how-to-replace-a-car-radiator
Jul 17, 2017 at 4:30 AM
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STRAILER
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It sounds like you may have a blown head gasket, please run this test:

https://www.2carpros.com/articles/head-gasket-blown-test

Please let us know what you find.

Cheers, Ken
Jul 17, 2017 at 9:34 AM
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NITRA22
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It is overheating but when the A/C is on it cools down a little and it look like thick orange stuff in the radiator vale. Can you tell me what is wrong please?
Sep 19, 2018 at 5:31 PM (Merged)
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WRENCHTECH
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Is that thick orange stuff feel oily?
Sep 19, 2018 at 5:31 PM (Merged)
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NITRA22
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No, it feels like when flour and water mix it is light and fluffy.
Sep 19, 2018 at 5:31 PM (Merged)
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WRENCHTECH
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You need to have that looked at to determine what that is before it does any damage. You are gambling with your whole engine there.
Sep 19, 2018 at 5:32 PM (Merged)
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NITRA22
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Okay, but is this why my is van overheating but not smoking?
Sep 19, 2018 at 5:32 PM (Merged)
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WRENCHTECH
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I have no idea until someone figures out what that stuff is.
Sep 19, 2018 at 5:32 PM (Merged)
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NITRA22
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It is rust and scale.
Sep 19, 2018 at 5:32 PM (Merged)
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WRENCHTECH
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Then you are probably going to need a radiator and system flush and go from there.
Sep 19, 2018 at 5:32 PM (Merged)