ok so heres the deal...86 gt bone stock....it has been running hot occasionally and acting like the tsats was sticking so i replaced it...let the car idle for about 20 mins and the temp went to hot...if i rev the engine for a few seconds the temp comes down...not sure how to check the water pump...its not making any sqeeling noises...the radiator looks original but seems in good shape inside...i have good heat..my other thought was ...i had the bottom of the exhaust apart and one of the rear stock cats was clogged so i reamed them both out but couldnt get the header to pipe bolts off so i couldnt check/ream the upper cats...could a clogged cat cause this problem?by thye way i put a 195 tstat in.and help would be great...thanx ...john

 

so if you drive the car does it overheats? or just at idle?check your fan clutch. have you pressure tested your car. i have a 195 but when i do my engine work i'm gonna put the 180 mr gasket thermostat in

 

i dont think a clogged cat would cause the engine to over heat, i would think that you would see it glowing red or it would be very sluggish, and possibly keep stalling, the easy way to see if your water pump is good pop open your raidator cap and watch the fluid on top, if it is swirling its good, it maybe hard to see sometimes...

but as for the over heating part i would tend to agree that your clutch fan is no good or your raidator is bad...if you can rev your engine and it cools down i would seem to me the water pump is weak, are you leaking any fluid threw the weep hole on the water pump you can see this hole on top of the water pump

 

not leaking any fluid at all....ive never been able to actually see the coolant swirling in any of my stangs...with the cap off it rises and falls...im thinking maybe the fan clutch...never had to deal with one but theres a first time for every thing...any idea how to check it? also how would i check the radiator for flow?...i was also under the impression that if my water pump was bad i wouldnt have consistant heat

 

i could always see my antifreeze swirling in mine, you look straight down at it at idel and see a small swirl going down the filler tube in the radiator

i dont really know how to check a clutch fan to see how it works i always ran a flex fan or an electric fanon all mine so i never had to deal with that problem, if it was a bad water pump as well you would still have heat because you heat comes from the two metal rails on the pass side of your intake located just behind your thermostat,just your flow will not be as consistant causing it to over heat faster

 

there should be no play when you grab the blades and move them side to side. it should feelvery smooth and kinda stiff. it shouldn't move freely.

 

Check all of your hoses, and your head gaskets.

 

thanx for all the input...hoses are fine and as for the head gaskets there is no oil in the coolant and no coolant in the oil.....im thinking water pump as there is definately no swirling in the radiator

 

20 plus year old car, could be a clogged radiator, was it ever flushed?

 

i suppose it could be the radiator...not sure if it was ever flushed....when the car is running at temp i feel no fluid moving in the upper hose...the lower hose feels warm and i see no fluid moving in the radiator