QuestionMy husband replaced a head gasket on a 97 Chrysler concorde 3.5, then the water pump and thermostat. Now it is still trying to run hot. He said it's boiling out the overflow jug.
AnswerHi Stephanie,
Is the excess white smoke from the tailpipe at start up, which indicates you still have a head gasket leak? An exhaust shop could also check to see if there is exhuast gas coming out the overflow bottle which would corroborate such a leak.
Do the two side manifolds of the radiator feel about equally warm, or is one side cooler than the other (which indicates restricted coolant flow through the coolant tubes)?
Here is a response I sent to another owner of the 3.5L which suggests other possibilities:
"I would look in to at least four possibilities: do you have sufficient coolant in the overflow bottle (there are lines on the side that you should have the coolant level in between, using a 50/50 mixture of antifreeze/water). Are there any signs of coolant loss under the engine compartment such as from a leak? (There will be plain water under the car after you have been running the air conditioner; I mean colored coolant on the ground?) Do you get an unusal amount of white smoke coming out of the exhaust pipe when you start the car from cold?
Then there are two other possibilities: there could be air trapped in the cooling system from not having it filled properly after the radiator (or the thermostat) was replaced. On the way to get air out:
It would be good to start with only a partially filled system, so drain off three quarts from the radiator drain.
Then notice that the thermostat housing has a bleed valve and a nipple from which you can drain fluid. Put a 4' length of clear plastic hose on the nipple and direct the hose over the front of the car to a clean container to catch the coolant. Then open the bleed valve. Then slowly fill the coolant recovery bottle until fluid starts to flow out of the clear hose. The gently squeeze on the top radiator hose until all the air is exhausted from the system. Close the bleed valve and fill the system the rest of the way until it reaches the to of the overflow on the bottle. Remove the hose from the bleeder valve nipple. You might be able to get the shop who did the radiator replacement to do this procedure for free, if they didn't do it right the first time.
Another possibilitiy is that the thermostat is opening at too high a temperature. This would be noticeable when you are driving at night or on cool days, and if you still notice the car runs hot. If it doesn't then this is probably not the cause of your problem. But observe how the gauge reads when it is cool outside as a test of this possibility.
The last thing is simple to observe: when the temp gauge goes up to about 3/4 scale or more are the cooling fans behind the radiator coming on or not?
So let me know what you learn, please."
Those are the other possibilities to consider.
Sorry for the delay but I just saw your question in the "pool".
Roland
