1999 pontiac Montana is over heating please help

[pandacare]

I have a 1999 Pontiac Montana was over heating but when you gunned the engine sometimes it would cool down I had my mechanic change the thermostat then it just shot up to hot when you drove around the block . we then changed the water pump and released all the air out of the lines changed the plugs and wire to make sure that it wasnt a head. it still is over heating .. does anyone have any other ideals????? please help!!!

[cdru]

Sounds like air stuck in the line. The cause can be an improper bleeding procedure, a lose connection, head gasket, etc.

[pandacare]

what do you mean by lose connection?

[pandacare]

What is the best way to bleed air out of my coolant system on my 1999 Pontiac Montana.

[cdru]

Originally Posted by pandacare

what do you mean by lose connection?

Sorry. Loose connection, like a hose clamp that has failed or a plastic fitting that has cracked allowing the once tight clamp to now be a little loose allowing air to enter (or coolant to escape).

[kfazzina]

I had the same problem, my thermostat was just changed a couple years ago, and the thermostat meter kepted jumping, the problem I found was that the thermostat was changed without proper bleeding of the coolant system.
I changed the thermostat, then I did the major bleeding from the colant filler, then kept bleading the coolant from the thermstat housing (there is a small bleeder on top) until the flow of coolant came out of the top of the housing with a good flow of coolant.
We bought the van brand new which is a 99 Montana currently with 123,000 miles, and my wife said that the meter does not jump. stays at 190 degrees, and that the heat works great.

[pandacare]

[thank all of you guys that gave me advice it was my head gasketafter all