Ok, my car will overheat only when i'm moving in 5th gear, or 4th for while like 5 minutes.. The temperature warning needle goes up to 220* then 240*, then i get nervous and slow down, and it cools down. I can drive in traffic 50 mph and slower all day long but once i get going about 60 for a few minutes, that darn needle starts wandering up! I have a 180* Thermostat, have a NEW Aluminum Radiator (Milodan) new Fan belts, and of course a new radiator cap. Should i run without a thermostat and see what happens? What is going on here? I really have no idea

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--Steve S-- 84 Trans Am 305 (cough)LG4(cough), 5 speed, Flowmaster 80 series, otherwise an emissions restricted slow 150 hp(chilton rating) 240 torquer that needs RELEASE!!!!

P.S. Daily Driver

 

Do you have a front air-dam? They work wonders . Its a little black piece that should be bolted to the lower radiator support. You can try driving without a thermostat it won't hurt anything if you're running this hot.

Oh yeah, is there anything else unusual such as glowing exhaust manifolds/Y-pipe/cat and is the overflow bubbling. If the overflow isn't bubbling and the radiator doesn't feel too warm it is possible that the sender isn't working however a bad thermostat will also leave the radiator and overflow tank cool.
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1984 WS6 Trans Am Hartop
Former L69 Car under restoration
1984 WS6 Trans Am T-top car
4-bolt main 350, headers, Holley 650, T-5 and 3.23's.
Daily driver and restoration
13.98 @ 101

[This message has been edited by 84FTA (edited January 12, 2001).]

 

Definitely check your air dam!!!! It's critical in the Pontiac because of the shape of the front bumper cover. Nowhere near enough air comes through the "grille" openings to cool the car; it relies on that lower air dam to scoop air up into the radiator. Also, there should be pieces on either side of the space in front of the radiator, that should make a closed "duct" out of the space up there, so that air can't bypass the radiator and go anywhere else.

I have a Z28 with a stock 83 electric fan cooling system; you can almost watch the temp gauge needle move down when you hit the freeway. I can sit idling and the temp will go up to 235 or 240° (stock fan switch), when the fan comes on; if it happens to be at that high limit, and I get on the freeway, within a mile it will be down to 180°.

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"So many Mustangs, so little time..."

 

I have an 89 T/A that did the same thing... new radiator, water pump, 180 t-stat,... replaced fans (originally had a low speed over heating prob)... then I noticed my air deflector was gone (teach me to let some chick borrow my car)... replaced that prob gone...

zroc

 

CAN anyone tell me if there is an upper or lower Air Dam? What are the part numbers if different?!

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--Steve S-- 84 Trans Am 305 (cough)LG4(cough), 5 speed, Flowmaster 80 series, otherwise an emissions restricted slow 150 hp(chilton rating) 240 torquer that needs RELEASE!!!!

P.S. Daily Driver

[This message has been edited by 84TransAm (edited January 15, 2001).]