1981 Turbo 4.9 Trans Am Overheating


Old 11-06-07, 01:48 PM
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Join Date: Nov 2007
Location: arizona
Posts: 1
1981 Turbo 4.9 Trans Am Overheating

Can't figure it out.. we changed out the sending unit,the thermostat, the fan clutch, the radiator cap, had the turbo rebuilt and it still overheats at anything over 2400 rpms...Some body said when the turbo kicks in the
extra pressure can cause an otherwise boarderline head gasket to leak..at highyway speeds of 65+ the temp climbs to 230 on the gauge..as soon as you back off the temp drops down to 215 ...never lower..the engine is the 4.9
ltr with 40,ooo documented miles and I am the third owner. The first owner was in Pa. and he told me that the car always ran too hot..but the guy that I got it from failed to mention this pre existing problem...Stupid me...No problem is unfixable but where do I start ? I am located in
Arizona and everybody knows how hot it is here most of the year..I really need some real help...I considered calling pontiac dealerships to try and find a mechanic who worked on these different cars back then but we all know how unhelpful dealerships can be and most of them couldn't care less and would rather sell me a new crate motor than have to have a mechanic think it through...I'm hopping that someone out in cyberspace san save the day. Many thanks johnny b good
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Old 11-06-07, 03:03 PM
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Join Date: May 2007
Location: Wisconsin
Posts: 8,629
Is it hot out when this goes on? HOW hot?

You running the a/c at the same time?

Are the a/c coil fins in front of the radiator clean along with the radiators?

You could experiment and take out the thermostat to see what your readings are then, under the same test conditions. -I- did that, to see what was going on, and that helped me discover my radiator was 1/2 plugged.

Does your car lose coolant mysteriously out of the radiator/overflow?

Keep in mind that witrh 50/50 coolant and pressure cap, your coolant will not boil until about 265 F degrees.

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