Chrysler Repair: 03 T & C: coolant loss, humid weather conditions, losing coolant


Question
QUESTION: My town and country is losing coolant. There is signs of water on the floor board, however no smell of coolant. It starts to overheat when I have the AC on...The other day it was cold and raining, I tried to use the heat I only had heat on the drivers side and the passengers side was blowing cold.

ANSWER: Hi Karen,
The water on the floor board might simply be condensation that normally occurs when the AC runs during humid weather conditions. That water is supposed to collect at the bottom of the HVAC box and drain out of a tube through the firewall that separates the cabin from the engine. That tube may be blocked up and thus the water which doesn't smell of antifreeze (I assume that you have still be adding antifreeze to the coolant when you replace it).
Do you see any water under the engine compartment when you park it? There shuld be a water only puddle under the midline of the vehicle at the firewall if the drain tube were 'open'. Puddles with coolant smell anywhere else would be a clue as to where you are otherwise loosing coolant.
The other possibility is that you have a leak inside the engine such that coolant is getting into one of the cylinders and then is blown out the tailpipe which would appear as excessive white smoke which if you allow that to condense on your hand would indeed smell of antifreeze. This would most likely be noticed when you first start the engine after an overnight cool down.
On the temperature difference between the passenger side and the driver side, that would likely be due to a malfunction of the air distribution door that varies where the air goes before it comes out of the HVAC box but would not be related to a loss of coolant. That problem should be addressed after you solve the leak location issue.
Please see the PS below.
Thanks,
Roland
Roland

---------- FOLLOW-UP ----------

QUESTION: There is a small puddle under the van when I park, it does not smell like antifreeze. No white smoke coming out of tailpipe. My biggest concern is it overheating, could it maybe be the thermostat? But that still does not explain the coolant loss. We lose about half gallon each oil change. Thank you for your quick responce

Answer
Hi Karen,
You would run the risk of loosing coolant of course if the engine temp gauge goes to or near the H, so that would be a time to check under the hood for steaming to see if that is the cause. Absent that, a slow gradual loss of coolant has to either be a hose/clamp leak, a radiator dampness/frank leakage, a leak in the HVAC box under the dash or at the rear cabin heater core (any wetness on the ground at the rear?), an internal engine leak (does the oil show any cloudiness?), or boil-off from the coolant overflow container when the engine is running hot.
Where does the gauge routinely sit after you have driven long enough to warm up the system? It should be below 3/4 scale if the amount of coolant in the system is correct. If higher then that, it would be worthwhile to change the thermostat.
Thanks for the rating and nomination, which you may do again if you would like.
Roland