Who did the replacement of the parts? Was it done at a shop or at home? Do you know if the cooling system was "burped" after the parts were installed and the coolant was refilled? If you're not sure, burp the radiator. This is easy to do. Jack up the vehicle so that the thermostat is angled upward. Start the car and let it idle until it's 3/4 of the way to overheating, then shut it off and allow it to cool down somewhat. Then pop the cap, let the coolant drain down, and refill it. Restart the vehicle and repeat the process, until the coolant level doesn't drop anymore.
What you're doing is this - anytime the cooling system is opened up, especially when the fluid is drained and parts are replaced, air gets into the system. When you reassemble and refill with coolant, you trap air bubbles in the system. Since the system is sealed, it operates under pressure. As the car runs, the coolant and the air bubbles are circulated. The bubbles get caught behind the thermostat (if you have it angled upward) and keep it from opening. This causes the engine to heat up to the point of overheating. You want to allow it to get about 3/4 of the way to an overheat so that you know the air bubbles are blocking the thermostat. Shutting down the car stops it from heating up to the point of damage, and allows the system time to cool off so that when you pop the cap, you don't get an explosion of coolant in your face. Once it's cool enough to open the system, you open it and release the pressure. This allows the thermostat to open and bleed the bubbles upward to the open cap, where they "burp" into the air. The space they took up fills with coolant, which is why your coolant level drains down. You top it off and repeat to make sure that all the bubbles are out. You'll know you're in good shape when you let it run and it gets to operating temperature and doesn't overheat anymore. Let it cool that final time, open the cap, and since you have no air pockets left in the system, nothing will burp out and your coolant level won't decrease. Then you should be good to go - put the cap back on and drive away happy.
Sep 27, 2008 |
1996 Jeep Grand Cherokee