No Heat, But Plenty Coolant

My 2010 Dodge Grandcaravan 3.3L recently stopped blowing out hot/warm air while driving. It comes and goes, but in short patched. There’s plenty of coolant, actually looks like more than original and seems some has came out from the overflow spout. Nothing foggy on windows, no weird smells. The van normally sits at the halfway mark on temperature, but was going as high as 3/4 way. When I showed down, the temp was dropping. Any ideas?

Have your van checked for a bad head gasket.

There are test strips that can be dipped into the coolant overflow bottle that can detect that.

Or when the engine is cold, remove the coolant reservoir cap, start the engine and let it warm up. If you see bubbles coming up in the reservoir, that’s a pretty good indication of a blown head gasket.


How warm? I saw a YT video that stated to do it cold and check for bubbles. I did, however, I did not see any bubbles. The reservoir looked more clear than the green antifreeze about 10k miles ago that the dealer replaced.

That’s why I gave you an alternate test. A compression test is also useful to detect a head gasket. A cold engine may not leak, a hot one will given your symptoms

And there is no need to go to the dealer for a van this old if you have a good local independent shop. And any shop should and will test to confirm your diagnosis.

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Yep, mustangman took the words out of my mouth. Whenever you see elevated temp in combination with no heat, think head gasket.

I spent a winter in Minnesota with a head gasket problem on my diesel. No heat in traffic until I’d get up to highway speed and enough force to overcome the air bubble. It eventually became a refrigerator or something.

I guess I will have to get a test done. The engine is hot/warm, but still no bubbles.

Did you see coolant in the radiator? With no heat and coolant overflowing from the reservoir, I would expect the coolant level to be very low in the engine cooling system.

If there is a head gasket leak, it is unlikely that you would see bubbles in the coolant during warm-up, the cylinder gases would be trapped behind the thermostat.

I did not look in the radiator itself. It works up to a point then stops for a few minutes then repeats. The thermostats was replaced within the last 12 months. This seems to have happen within a day or two after getting spark plugs, wires, and the spark plug ignition coil replaced.

You won’t see air in the cooling system if you don’t look.

Inspect the heater hoses for leaks or a kink in a hose, these can be difficult to see behind the intake manifold.

You need to check the coolant level in the radiator. Make sure that the van is completely cool before removing the cap!

Thermostat installed backwards?

Was a common mistake 40-50 years ago.

If you are a DIYer, you could test for the presence of combustion gases in the coolant with something like this:

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Several other common possibilities should be considered before focusing on a potential head gasket problem

  • Cooling system pressure cap gasket is leaking, and not allowing the cooling system pressure to maintain the correct operating temperature.
  • There’s a similar coolant system leak, but from some other spot, like the water pump.
  • Air pockets forming in cooling system
  • HVAC system’s warm-air routing doors are not moving into their correct position.
  • HVAC’s blower not working
  • Hot coolant is never reaching heater; e.g. pinched hoses, as mentioned above.

Another place to check for a leak is shown in the video below. It is a very common problem on Caravans from 2008 to 2018 I think. it can start of as a slow leak that you may miss. the new kit for the y-pipe is now made from aluminum.

Dodge Grand Caravan Coolant Leak - Simple Fix - YouTube