I have a 1997 Monte Carlo with the 3.1. The intake gaskets were replaced about 3(?) years ago.
A few months ago, it pegged the temp and blew cold air. I changed the thermostat (NOT an easy job) and the problem was resolved.
The problem recurred a few days ago. The oil looks fine, coolant might have been down just a bit, no white exhaust. No noted leaks. The water pump is about two years old. The belt is good, I see no slipping.
While driving, the car wil appear to be heating up appropriately. I will start to get some warmth from the heater, and suddenly it will be cold and the temp will shoot up to max. Just as suddenly, it may resolve.
In fact, I drove to work yesterday and averything was perfect. When driving home, the issue happened twice, but resolved by the time I was half-way home.
It may be coincidence, but I wondered if coolant wasn't reaching the thermostat (secondary to a bubble, obstruction or low coolant), so I hit the brakes hard and made a sharp right-hand turn. I figured it might force the coolant to the thermostat-side of the engine. Right after I performed this maneuver, the issue subsided.
I have exchanged some of the coolant, topped it up and burped it repeatedly. When I replicated the problem in the garage, the top radiator hose was of course cold, the fans ran ok.
I did notice some very gentle bubbling in the overflow tank while the engine was running, maybe 1 bubble/second. I replaced the radiator cap.
At one point, when the problem occured over a prolonged period, it nearly overflowed the overlflow container, but it sucked it all back in overnight.
There is another potential clue. I was replicating the problem, and burped the system via the port on the crossover tube which is hear the water pump. A lot of air was expelled, and the issue resolved. (For reference, I have jacked the front of the car up in order to help expel all of the air).
I'm not sure if it is losing coolant. It may have lost a bit yesterday, but I will need to keep a close watch.
I have the issue narrowed down to the thermostat, an intermittent blockage behind the thermostat, air in the system, leaking intake, leaking headgasket/cracked head.
The intermittent nature is throwing me.
I devised a radiator cap with a pressure gauge (to see if exhaust gasses are pressurizing the cooling system) which I will try tomorrow.
Almost forgot to add: prior to the intake gasket repair, I had added some Bar's stop leak (the black colored rhizex pellets), and have expelled some of it. I wondered if it could be causing an intermittent obstruction.
Ok, I need some BITOG help! Whaddyathink?????
A few months ago, it pegged the temp and blew cold air. I changed the thermostat (NOT an easy job) and the problem was resolved.
The problem recurred a few days ago. The oil looks fine, coolant might have been down just a bit, no white exhaust. No noted leaks. The water pump is about two years old. The belt is good, I see no slipping.
While driving, the car wil appear to be heating up appropriately. I will start to get some warmth from the heater, and suddenly it will be cold and the temp will shoot up to max. Just as suddenly, it may resolve.
In fact, I drove to work yesterday and averything was perfect. When driving home, the issue happened twice, but resolved by the time I was half-way home.
It may be coincidence, but I wondered if coolant wasn't reaching the thermostat (secondary to a bubble, obstruction or low coolant), so I hit the brakes hard and made a sharp right-hand turn. I figured it might force the coolant to the thermostat-side of the engine. Right after I performed this maneuver, the issue subsided.
I have exchanged some of the coolant, topped it up and burped it repeatedly. When I replicated the problem in the garage, the top radiator hose was of course cold, the fans ran ok.
I did notice some very gentle bubbling in the overflow tank while the engine was running, maybe 1 bubble/second. I replaced the radiator cap.
At one point, when the problem occured over a prolonged period, it nearly overflowed the overlflow container, but it sucked it all back in overnight.
There is another potential clue. I was replicating the problem, and burped the system via the port on the crossover tube which is hear the water pump. A lot of air was expelled, and the issue resolved. (For reference, I have jacked the front of the car up in order to help expel all of the air).
I'm not sure if it is losing coolant. It may have lost a bit yesterday, but I will need to keep a close watch.
I have the issue narrowed down to the thermostat, an intermittent blockage behind the thermostat, air in the system, leaking intake, leaking headgasket/cracked head.
The intermittent nature is throwing me.
I devised a radiator cap with a pressure gauge (to see if exhaust gasses are pressurizing the cooling system) which I will try tomorrow.
Almost forgot to add: prior to the intake gasket repair, I had added some Bar's stop leak (the black colored rhizex pellets), and have expelled some of it. I wondered if it could be causing an intermittent obstruction.
Ok, I need some BITOG help! Whaddyathink?????
Last edited:
