2000 Pontiac Grand Am leaking

Engine Cooling problem
2000 Pontiac Grand Am 4 cyl Two Wheel Drive Automatic

my car is leaking coolant out of the thermestat housing I took it of and replaced the thermastat and gasket but it didnt fix it but when I took the thermastat out and made a gaskit out of high temp silicon it fixed it for a while then started leaking again what could be wrong with it
Do you
have the same problem?
Tuesday, November 17th, 2009 AT 12:39 PM

1 Reply

Kudos for even attempting this one, those are tough. The suggestions we make are based on experience and not to put anyone down. Information that I know about replacing this thermostat is that it is a process. If the mechanic tries to cut a corner the gasket leaks. That being said, keep these notes in mind:

1) The old thermostat gasket or part of it is probably lodged in the housing preventing the new seal from doing its job. This repair is difficult and I have missed it once my self because of the restricted space.

2) The bolt that connects part of the steel coolant line to the exhaust must be removed and reinstalled AFTER the thermostat housing bolts are tightened.

3) When tightening bolts do it in steps, little by little, side to side. Fully tightening one bolt all the way and then the other can cause the component to tilt to one side and cause a leak.

The process to do the job:
The thermostat is located under water pump, follow bottom radiator hose, it connects to metal pipe (water inlet pipe) which wraps under engine. At the end of this pipe where it connects with water pump is thermostat. You will access thermostat through the top of engine. To start you will need.
3/8 socket wrench
3/8 universal socket (swivel)
3/8 extension (7 or 10 inch)
8mm socket
10mm socket
13mm wrench
thermostat gasket.
Jack stands
Drain Pan.

You will need to lift the car. (Never work under car without proper support)
When you separate the connection where the thermostat is housed you will loose a lot of your coolant.
1. Lift and support front of vehicle, (set parking brake, support car on stands, I used concrete blocks)
2. Remove Heat Shield, inside engine compartment behind engine is your heat shield, it is held on with 3 10mm bolts.
3. Separate connection that holds in thermostat. This is a little tricky, assemble wrench starting with wrench, extension, swivel, 8mm socket. Standing at passenger side fender, reach behind and under manifold with left hand and find 2 bolts on top of water pump, then place socket wrench through the manifold between the 2nd and 3rd pipes. With your left hand guide the socket onto the bolts and remove.
4. Remove 13mm bolt that holds the black water inlet pipe in place. Underneath the car, follow the black pipe that wraps under engine until you see a bracket. Remove the bolt that holds bracket.
5. Remove thermostat. Standing at passenger side fender, with left hand reach behind and under manifold and remove thermostat, it will be in the black pipe.
6. Install gasket on new thermostat. Look at your old one for reference.
7. Install new thermostat. Place new thermostat in Black pipe, the spring facing up toward engine.
8. Replace bolt for water inlet pipe. Replace the 13mm bolt which held the pipe bracket to engine.
9. Replace 2 8mm bolts that hold Water inlet pipe to water pump. The same way you removed them left hand behind and under manifold (bolts in left hand). Start one bolt then start the other. Tighten your second bolt about half way then switch. Repeat and make sure both bolts are snug.
10. Install Heat shield. 3 10mm bolts.
11. Fill with coolant, and perform bleeding process.

Good luck.
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Wednesday, November 18th, 2009 AT 4:17 PM

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