bbbngowc

If my car is at idle, it'll temp gauge will rise nearly to top, but when I press the accelerator, the temp will go down to about normal. As soon as I stop again and idle, it starts to over it. I would have to take it out of gear and rev the engine for it to cool down again. I'm thinking water pump, but could it be something else?

1991 GT 5 Speed
CAI

nseoi

thermostat is cheap and easy. i replaced mine for the first time the other day and it took me 30 minutes cause i was in a dark parking lot and the car temp never goes past like 56%

i would change that first since its quick, should be part of a tune up its that easy

AdderMk2

its either the water pump, or a radiator/fan issue

brentloftis

Do the thermostat like the other post says but I suspect a blockage in the radiator or the fan not coming on. Do you have under drive pulleys? You can also try turning the AC on to turn the fan on to see if it helps.

hemi_04d

Sounds like the fan isn't spinning fast enough at idle, or water pump isn't moving the coolant.

bbbngowc

The Radiator is new and the clutch on the fan is bad so, the fan doesn't stop spinning. Now I'm even thinking a pulley is the cause, cause I noticed that when I'm at idle the voltage gauge also drops below the half marker. As long as I'm about 1000RPM the voltage guage and temp gauge is mid-way.

Still think it's the waterpump?

AdderMk2

do you have underdrive pullies?

its NOT your thermostat

Sxynerd

Time for a coolant system make over. I'd think about replacing radiator, wp, thermostate and coolant lines. When stuff starts happening it's ususally because of years of neglect. Replace it all and do your PMCS.

bbbngowc

No underdrive Pullies, although I recently replaced my alternator with a 140AMP and the pulley on it looks a bit small.

Radiator and Hoses are new (less than 3 months).

AdderMk2

a small pulley on the alternator is a GOOD thing