Overheating and don't know why

[crcarey1]

I have a '99 Montana 3.4L. Just had the rear head gasket replaces due to leaks and overheating. Now that that is done, the thermostat, coolant sensor, radiator cap, and water pump have all been replaced. The car runs hot within 5-7 miles. Overheats and shuts off. I have replaced everything I can think of. I've bled the coolant system. The fans work fine so I haven't replaced the two relays. I'm at my wits end. Any suggestions?

 

[booda]

mine is the exact same thing...please somone offer some insight if you have it regarding this problem.....

 

[Violator]

First of all. Why only one head gasket? Head gaskets should always be done together at the same time especially with the 3.4. I've seen these engines blow head gaskets then overheat to the point that the head casting actually deformed and shrank to the point that some of the head bolts could be removed with your fingers. These engines are prone to lower intake manifold leaks, blown head gaskets and cracking heads. Usually once one head gasket goes the engine will overheat and create problems with the other side hence why you do both at once. Even though the initial compression test only shows one, once it is changed the other weaker side lets go.

Another area to check is the water pump. Is it pumping coolant? Is the thermostat stuck shut? When the gasket was done was dexcool or Global antifreeze used to refill? If the regular green was used and allowed to mix with the existing dexcool it will gel up and not circulate.

Check into the above and let us know your findings.

 

[booda]

I only had the lower intake repaired because that is all I was informed of, I not a mechanic..lol...anyways, I had thermostat replaced and took care of the spiking temp but, was still going up to about 230 then down to normal...heat was sporadic...I went this morning and low coolant light came on...took it to have radiator fushed and they said fluid looked clean but it was about a quart and half low on anitfreeze...they topped it off and was running great constant temp at 160 even heat...as I was pulling in the drive low coolant light came on again..heat was fine temp was still running at 160....so, thats where I at now... gonna run out and get some dex and see how much more it takes....

______________________________

 

[Violator]

Need to have the cooling system pressure tested to see where the leak is at. Check your oil and make sure it doesn't look like chocolate milk and overfull.

 

[booda]

head gasket......another 1500.00 into this van....at least it's paid off....I debated trading it in...but aside from the gaskets on intake and head it not a bad van.....very few problems otherwise.. I will run it into the ground now though.....and thanks for all your help I appreciate it!!! merry xmas everyone