overheating problem

[eric@medmd.net]

i just got a 1989 supra. it keeps overheating. i change the water pump, thermostat, and flushed out the system. yet and still, its overheats. i do not see any fluid on the ground. when it runs hot, steam hits my overflow. i must add fluid ever time i drive it. please help???

[toyomoho]

Does the engine overheat in traffic, on the hwy or both? Check to make sure the coolant fans are working OK, radiator hoses not collapsed, T-stat installed correctly, radiator not partially plugged, no air in coolant system. Make sure the head gasket is not blown, cylinder or block has a crack.

Also check the posts at the end of this page for more ideas.

[eric@medmd.net]

i had my value cover gasket just done. its stay heated while driving and standing still with the motor running. i also just had a tune up. when i full it up, i let the heater run at 85-degrees. the heater just blows, with on heat, or a/c. i was going to take care of that next. the cooling fan trys to cool it off, but that only works for a short time. thanks

[toyomoho]

If the car is operating at road speeds, air going through the radiator should be sufficient to keep the engine cool. Check to make sure the car has all the air shrouds and dams it supposed to have. They keep the air directed through the radiator.

In stop and go driving or standing still, the radiator fan should turn on at around 199F to cool down the coolant then turn off. You can use something like a meat thermometer installed where the radiator cap goes to measure the coolant as it warms up.

Head gasket not valve cover gasket. A leaking head gasket can cause exhaust gases to flow into the coolant, forcing it out. A shop can perform a simple test of the coolant for exhaust gases and do a coolant system pressure test.

Check for collapsed bottom radiator hose. When engine hot, compare upper and lower radiator hoses to see if both are about the same temp. The radiator can be partially plugged on the inside, or the outside fins.

[theKnifeArtist]

coolant pressure test isn't necessarily a good way to test your head gasket. leakdown test would be better. mine would overheat, coolant overflow out of the resivour..yeah..big mess. sure enough, blown head gasket it was. that's what the 7M does. it blows HGs.

[Jeeves]

I'll throw my pot into the "Head Gasket Failure" pot.

[zachm611]

i too agree with the BHG.. maybe possible bad fan clutch? or even a bad radiator, i recently changed my HG it wasnt too hard of a job. i also got a new koyo oem radiator and now i have no cooling problems even on 6+ hour drives. good luck you can either get a test kit from napa or take it to a shop for testing if the HG is bad. and another way is compression testing.