Overheating

cavalier
chevrolet

#1

2002 Chevrolet Cavalier transverse 4 (2.2L)

New head, gaskets,bolts. Suspected heater core defective, coolant lines to heater core disconnected. New thermostat.

Car immediately overheats w/i 1 mile from cold block (ambient temp less that 60 degrees). Pressure builds up in expansion tank, bleeder line blows coolant into engine compartment. After engine shut down, pressure at cap relieved, car runs OK. Please help…driving me nuts! RK


#2

Why was the head replaced? and are you sure you got exactly the right head and gaskets. When it overheats is the radiator getting hot? Have you done a pressure test on the cooling system? Does the fan run when it overheats?


#3

sometimes the “fins” on the water pump disintegrate and it will not pump or push coolant. it is worth the trouble to pull the pump and look. worst thing that could happen is a little time spent and a new gasket for the pump


#4

Head was cracked, head gasket blown. Sure of right head and gasket set. Water pump replaced.Radiator NOT hot,coolant in expansion tank warm. Thermostat replaced three times. Fan runs when hot. Pressure test done.


#5

Head was cracked, head gasket blown. Sure of right head and gasket set. Water pump replaced.Radiator NOT hot,coolant in expansion tank warm. Thermostat replaced three times. Fan runs when hot. Pressure test done.


#6

There’s an air pocket in the system somewhere, most likely in the engine itself after the car sits for a couple hours, which is why it overheats so quickly, and why there’s air in the system that needs to be bled off.

If you can get a vacuum system to bleed the cooling system, and refill it that way, you might be able to eliminate the issue.

BC.


#7

If the engine is building up sufficient pressure to blow coolant out the system within one mile of driving at an ambient temperature below 60 degrees, the symptom almost has to be being generated from somewhere other than the engine overheating. No engine is going to heat up that fast at that temperature.

However, any temperature rise is enough to cause pressure to blow IF the expansion tank is not capable of withholding the pressure it should. I’m assuming that on your system the pressure release is on the tank rather than the radiator, making it a true expansion tank rather than just a reservoire. Correct me if I’m wrong. In short, check the pressure rating of the tank cap (it should be about 16 PSI) and either test or replace the cap.

If you’re concerned that the engine is actually overheating, I’d suggest a seperate temp gage on a “T” fitting. I’ll bet it’s not getting even up to full operating temp when the symptom occurs.


#8

In my experience the cause of such immediate overheating has turned out to be exhaust gasses contacting the coolant. You should preform a test to check for the presence of hydracarbons in the coolant.