overheating at idle

[89supra884]

well i mean it was working fine for a couple weeks which means even if i would have tested it it would have opened, but its just like over time, is when it goes bad, and this is going to be like my 3rd or 4th thermostat, i mean is it the thermostat or something else

 

[wiseco7mgt]

well i mean it was working fine for a couple weeks which means even if i would have tested it it would have opened, but its just like over time, is when it goes bad, and this is going to be like my 3rd or 4th thermostat, i mean is it the thermostat or something else

Have you checked the clutch fan yet? swap one off a working vehicle, they are quick to change over and cheap to buy.
If the car still overheats get an old thermostat and cut the guts out of it just leaving the main plate and then put that back in the car and see if it's still overheating.
If the car still overheats you'll need to then have the radiator checked out, make sure the water pump is working,e.t.c

 

[cuel]

Search here for Jetjock's thread on how to rebuild the fan clutch. Parts are easy to get(just need some R/C shock oil, iirc, just don't remember the weight), and pretty easy to do.

 

[tbcmorris]

i had this problem in my old supra. after running through the diagnostic process it was the heater vale on the fire wall. the one that is control by vacuum.

i ended up getting rid of it. my heat isnt as hot but i really dont care because i park my supras in the winter.

while i was rebuilding the new supra from the fire damaged i carried this mod over to the new one. the right way to fix it is to replace the faulty part....my mod has worked fine so far.

 

[cheverlot]

mine was doing that for about 6 months it ended up being a head gasket does it only do it if it idles for a few mins?

 

[jetjock]

3000 centistokes for the oil.

I agree this sort of symptom (overheat at idle but not cruise) is indicative of airflow problems, either a bad fan clutch or external blockage of the radiator. Could be be the rad is partially blocked internally too. Best way to test that is with an IR gun...

 

[Poodles]

Could also be a bad waterpump (rare, but does happen)