We drive a 2004 Dodge Caravan with just over 150,000 km with the 3.3 litre V6 engine.
The engine coolant has been flushed and refilled.
About 3 months ago, while stuck in traffic, I noticed steam coming off the hood. Turned the heat to high and opened the windows. The temperature gauge remained in the acceptable range. When I parked the car and opened the hood I noticed that the coolant overflow was dry. Let it cool down and added some coolant to the overflow and the rad.
A couple of weeks ago, while stuck in traffic I again noticed steam. When I opened the hood, I noticed that the overflow was very low (but not empty). The radiator was full. I added more coolant to the overflow tank. Again the temperature gauge remained in the acceptable range.
This has only happened when caught in city rush hour traffic. Luckily most of my driving is outside of the city and on highways.
I watch carefully and have not found any signs of coolant leaking from the car (at least in noticeable amounts).
Of course I am worried that there may be a head gasket problem and coolant is leaking into the engine that way. However when the oil was changed there was no sign of this and the coolant in the radiator does not show any signs of contamination.
It has been suggested that this could also signal a problem with the PVC. Another person who had a similar problem stated that changing their radiator cap solved it.
Your suggestion(s) would be greatly appreciated particularly as if it is a head gasket problem it may not be worth repairing.
Thanks and if it is a serious problem I will be attempting to trade it in.
I have some bad news for you Worried, the 3.3 and 3.8 litre engines has a history of chewing up and spitting out head gaskets.
I am impressed with your diagnosis by considering coolant and oil condition as a result of this possible leak - the unfortunate thing is that rules don't always apply to all engines. Also you need to consider the different levels of failure severity.
You are right in assuming that you should normally see at least a hint that either oil is leaking into the coolant or that coolant is leaking into the oil. One way to check is to remove the oil filler cap and inspect the bottom of the cap and the cavity just below its threaded mouth. The presence of water in the oil shows up as a caramel-coloured foam.
And vice versa, to check for oil in the coolant, remove either the overflow cap or the radiator cap and looking for a brown oily film on the surface of the coolant or the plastic walls of the overflow tank or the inside of the radiator. But again, I want to bring to your attention the level of severity. The simple fact that you can go for many days without a major symptom tells me that the leak across the head gasket(s) is marginal at this time. But Worried, don't remain complacent and ignore this situation because it will get worse and it will ramp up quickly.
It gets worse because as coolant gets burned in the combustion chamber, the glycol will begin to contaminate the oxygen sensors and the catalytic converters.
Given the age of the vehicle and history of these engines, you might want to get serious about trading in your van. But be honest with the buyer/dealer, you will need to disclose the defect. It will beat up your trade-in value, but you would have been bucks down anyway, if you repaired the engine prior to dealing it away.
Buy a vehicle that retains its resale value well