2001 Cavalier 2.2 Engine Runs Hot

1. Car does not boil over, but runs approx 225-ish or higher (major div between 195 mark and 260 mark)

2. Checked sensor and gauge by dunking sensor in a pot of boiling water, gauge reads about 195 just after taking pot of water off the stove.

3. New Water pump (aftermarket - advance auto) 4. New T-stat (180 degree, advance auto says OEM replacement).

5. Removed radiator, flow checked fine. reinstalled.

6. No T-stat is not in backwards; Button faces the water pump.

7. I believe the flow goes from water pump to T-stat housing, splits toward heater core and radiator (through T-stat) then out of radiator through metal crossover tube back to passenger side of engine block.

8. Electric fan starts when gauge reads around 200 plus. With fan blowing, air coming out back of fan is COOL.

9. When running, and hot, I can wrap my hand around radiator hose running from T-stat to Lower Radiator inlet, and the hose is not even warm. Heater hose is too hot to touch.

10. Not losing any coolant.

11. Heater will drive you out of the car.

12. Place my hand on the radiator core with car running and hot, core is COOL.

13. Remove T-stat, repeat all tests and...

13.a. Lower Radiator hose is hot.

13.b. Radiator Core is hot.

13.c. Engine runs much cooler (too cool, I know I need a T-stat)

13.d. Fan comes on when engine gets to about 195, then gauge drops like a rock but fan never shuts off.

14. Yes, I have bled the air out of the system. I know where the bleeder valve is.

15. Yes I am running with the expansion tank pressure cap installed.

16. I work in a calibration lab. Took T-stat dunked it in a stirred water bath monitored with a lab grade platinum resistance thermometer. Starts to open at 180, at 195 its open about 1/8th inch. Dunk it in boiling water on the stove (212) it opens wide open.

17. Checked for mechanical interference in the T-stat housing and can find none.

18. Got Advance Auto to replace the T-stat, exact same symptoms. I have done my own auto repairs for years (51 years old). I am sure there is something basic I am missing here, but have talked to many people who know a little bit. No one can see anything I am doing wrong. Any clue?


Answer: Obviously this is a flow through the radiator problem. Radiator should be hot all over. The fans continuing running after they start is sort of a common characteristic of this car / engine. If you only put your hand to 1 part of the radiator, this is not enough. There could be a restriction in another area, or areas of the radiator. Using a laser thermometer on several areas is a good test for a plugged radiator. With the thermostat out, flow is better, so also could have a restriction before the thermostat. Would also like to see you get an exact temp of the coolant at the upper hose. Just using the gauge can be misleading. Coolant flow goes into the radiator from upper radiator hose, then cools, then out to lower hose.

Cavalier Radiator Fan Temp

what temperature the fan turns on for Chevy cavalier 2000 2.4ls twim cam ?

Answer: The radiator cooling fan will turn on in 2 stages. The first radiator fan speed will come on at about 226 degrees, the second and faster speed will be at about 250 degrees. If they are not coming on at all, check the coolant temp sensor, check all fuses and relays. Then test power power and ground at fan when correct coolant temperature has been reached.

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  • Guest - THE DEVIL

    Put a can of Draino in the cooling system... This will make a huge differance.... I promise!