After a week on the road and several white smoke filled startups, my car decided to overheat today. I have realized that I will be doing a headgasket this weekend but I just thought this was a weird overheating condition.
The car was having some smokey startups since I finished the swap a few weeks ago. I thought maybe it was just condensation in the exhaust because it would stop after it was driven about 100 feet. I was wrong. So far as I can tell, the headgasket was leaking between cylinder 3 and a coolant passage. This resulted in a situation in which the cylinder was pumping air into the cooling system and pressurizing it. When the car is shut off, the residual pressure in the system pushed coolant into the cylinder, causing the smokey startup.
The car ran fine like this for a while but today it got much worse. Sitting at idle in the inspection station (ironic, I know), the cooling system pressurized to the point where it ballooned out the sides of the reservoir (rad mounted m42) and blew the pressure relief on the cap, spewing coolant all over the engine bay and floor.
I have a pusher slim fan on the radiator and when I think about it, I don't think it was running when the car overheated. The fan is hooked up using the aux fan wiring and should have been running as the temperature went up.
The fan works fine when the a/c button is on, and had previously worked perfectly at maintaining temperature on its own.
Is it possible that the leaking head gasket just formed a big bubble in the part of the radiator that has the temperature sensor in it, preventing it from getting an accurate reading? Or could the leak have prevented the passage of coolant into the radiator?
After replacing the thermostat and bleeding the system, I took it around the block. The gauge shot right back up. I used an infrared thermometer and saw that the radiator was 90 degrees on the one side, 120 on the other, and the upper rad hose was hard as a rock and 150 degrees.
I'll be replacing the headgasket this weekend, but it just irks me that I can't say for sure why the fan didn't come on by itself and made the car overheat.
The car was having some smokey startups since I finished the swap a few weeks ago. I thought maybe it was just condensation in the exhaust because it would stop after it was driven about 100 feet. I was wrong. So far as I can tell, the headgasket was leaking between cylinder 3 and a coolant passage. This resulted in a situation in which the cylinder was pumping air into the cooling system and pressurizing it. When the car is shut off, the residual pressure in the system pushed coolant into the cylinder, causing the smokey startup.
The car ran fine like this for a while but today it got much worse. Sitting at idle in the inspection station (ironic, I know), the cooling system pressurized to the point where it ballooned out the sides of the reservoir (rad mounted m42) and blew the pressure relief on the cap, spewing coolant all over the engine bay and floor.
I have a pusher slim fan on the radiator and when I think about it, I don't think it was running when the car overheated. The fan is hooked up using the aux fan wiring and should have been running as the temperature went up.
The fan works fine when the a/c button is on, and had previously worked perfectly at maintaining temperature on its own.
Is it possible that the leaking head gasket just formed a big bubble in the part of the radiator that has the temperature sensor in it, preventing it from getting an accurate reading? Or could the leak have prevented the passage of coolant into the radiator?
After replacing the thermostat and bleeding the system, I took it around the block. The gauge shot right back up. I used an infrared thermometer and saw that the radiator was 90 degrees on the one side, 120 on the other, and the upper rad hose was hard as a rock and 150 degrees.
I'll be replacing the headgasket this weekend, but it just irks me that I can't say for sure why the fan didn't come on by itself and made the car overheat.
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