Last post on Nov 03, 2010 at 7:32 AM
You are in the Pontiac Montana
What is this discussion about?
Pontiac Montana, Van
#1 of 2 Montana overheating w/ cool engine
Nov 01, 2010 (8:40 pm)
My daughter has an '02 Montana (approx 145K miles). It used to give her an warning msg that the coolant was not up to temp. Now it says it is overheating, when she is just starting out for the day (I know we are in Houston, but it is not that hot in Oct.). When it reaches some level, it tries to shut down. Not good when there are kids in the car. One timne it was "overheating" she could not only touch the radiator cap but the block w/o any serious heat level. She said her husband had the sensor replaced, but it has not changed its behavior. Radiator & water pump less than a year old. Any ideas???
#2 of 2 Re: Montana overheating w/ cool engine [icepatrick]
Nov 03, 2010 (7:32 am)
Not sure if you read my post under "kennie" but I had all kinds of heating/over-heating issues about 2 years ago - you can read my posts. What I believe was happening is that my head gaskets were showly failing (the original ones are crap and do not withstand the temps of 3.4L), the new gaskets have been fixed over the last 4 years or so from what i've heard. I suspect a leak in the system letting air into the coolant creating air pockets that do not allow the coolant to flow. I thought I had solved the problem by flushing and back flushing my system (see my long posts under kennie) but then about 4 months later my gasket blew... cost me about $2600 to re-do the heads/gaskets and I also had a heavy duty radiator installed at the same time. My van had been running better than ever now and because they had to shave the heads I have more compression and feel that I have more power. Unfortunately head gaskets are a major problem in these years of montantas. Hopefully it is something else but there is not much that can go wrong... blockage (I doubt that and if it is a flush forward and reverse would work - see my posts under kennie), pump (you just replaced it and the symptoms have not changed), air pockets caused by leak in radiator (this should not do it either b/c the fluid would only come out... holes would not be big enough to let air in), air pockets from head gaskets (most likely, but not for everyone... maybe a coolant presure test can determine this, not sure). I would not run the engine if the coolant is not heating up within a few minutes - you could fry your head gasket and it will let go. If the head gasket does let go and you get grey smoke out the tailpipe or it starts to run really rough, do not drive the vehicle, have it towed, if you drive it the rods could get bent and then you need a whole motor overhaul - worth much much more than the vehicle. I personally would start with a coolant presure test (overnight if possible) then a coolant flush (backwards FIRST AND THEN forward - ask them about this). I did the coolant flush mostly because I was not getting heat in the vehicle (canadian winters) and it worked for me... but then later found out that really air was getting into the coolant eventually through the failing head gaskets. K