QuestionHello,
My 1999 Town and Country 3.8L van recently started overheating. Just a little at first with a some coolant loss that I could not track. The temps would only get high after I had lost about 1/2 gallon of coolant over time. If i refilled, all would go back to normal.
Then it got worse and I noticed it was leaking and hissing from the upper radiator hose area at the neck (hard to see exactly where due to the radiator upper support). All I could see was where the vapor would hit the upper support, condensate and then run down to the cowling underneath. I also noticed the upper radiator hose would be rock hard and hot. I suspected the thermostat was stuck closed causing an eventual heat and pressure build up that was finding its way out via the upper radiator hose/neck.
I replaced the thermostat and flushed the system. Tested for many hours both driving and during idle. Temps maintained and there were no leaks for a few days. It seemed the issue had been fixed.
Now suddenly it is leaking at the same area again (under the support somewhere at the upper radiator hose/neck. It is very hard to tell what exactly is leaking, but it only does it now after I have ran the vehicle to warm and then park with the engine off. I suppose without the coolant flowing that the temp and pressure builds up and it starts leaking again. Fortunately the upper hose is not getting rock hard anymore and I am able to squeze it (so the thermostat must have fixed some of the problem).
My question is: could a stuck thermostat possibly have caused the plastic seals in my radiator to have blown or develop a small leak? I am going to replace my upper radiator hose and clamps tonight and see if the problem persists. If so, I will assume it is the radiator (I just cannot get a good look at the upper radiator hose/neck area to see if it is coming from the neck or the side of the radiator.
Also, it is not overheating, just hissing and leaking after I park. It will hiss for a few seconds and then quit. Then it comes back and quits. It will do this for some time (I guess pressure is being released and then building back up and causing a leak again). Is this indicative of a bad seal in the plastic radiator housing, or could it be as simple as the upper radiator hose itself. Aghain, the temps are staying right at mid level and I am only losing about 1/2 gallon of coolant from this vapor/leak at the upper hose/neck area.
I am hoping that you have heard of this hissing and stopping and repeating after the vehicle is warmed up and parked. Any advice or sugggestions on how to check without tearing the radiator out would be greatly appreciated.
And...if I do end up needing to replace the radiator...any tips or pointers would also be appreciated (looks to be a little bit of work with the limited room I have to work with). Thanks in advance for your reply.
AnswerHi Derrell,
I haven't heard of this specific issue. But I would not think it is related to the thermostat history, but rather too something related to the radiator or the hose connection to the manifold. The coolant leaves the engine and flows to the radiator thru that top hose, so if it backed up it would be at the radiator not the thermostat.
I have the instruction for replacing the radiator if that is necessary so let me know and I can xerox and postal mail it to you.
So see what you can observe when you check the hose/clamp interface with the radiator and let me know. It may be a partially obstructed flow thru the radiator which would manifest itself by being quite different in temperature on the two manifolds at either side.
Thank you for the detailed history and description.
Roland
