I have an 83 Trans Am with a 350 V8 engine swap. I’m having a problem with the car getting too hot. It gets to about 220 and goes to 240 with the air on. I had a new radiator put in, a thermostat (195 degree) a new digital temperature gauge and sending unit. The mechanic said that the sending unit is to close to the exhaust on the engine and it give it a false reading. But that doesn’t sound right to me. What else can I check?

Also I’m in Orlando and it anyone knows a good mechanic or can help me out. Please send me an email.

Jim
Starbuck@gate.net

 

Assuming your fan is electric.
I hope it is. I don't know if these cars had belt driven ones.
I think the fan isn't set to go off until anywhere near..223..224..something like that. You can buy a cooler fan switch to turn it on at lower temps, for example, the Jet part no #60600 turns the fan on at 200* and off at 185*. Just a suggestion. Not too sure it fits your problem.

 

Couple of thoughts....

First things first, confirm that your gauge is accurate, before you start running in circles. Might be a good idea to temporarily hook up a known good mechanical gauge, for comparison.

Make sure that electric temp gauge has a good ground. Although GM gauges normally read lower with increased resistance, there may be some aftermarket gauges that work the other way.
Teflon tape can on occasion interfere with a sensor ground path (usually not, but it can happen). If in doubt, run a ground wire all the way up adjacent to the sensor.

If you're using the original fan setup from the '83, perhaps a bad or slipping fan clutch?

Did you test the T-stat before installing it?

Is the idle speed correct, after AC clutch activation?

Ignition timing correct on the new engine?

Oh, FWIW, that Jet fan switch is the same as what GM used on '89 Turbo Trans Am's, and '86-'87 Buick Turbo Regals. You can get one at just about any parts counter for a lot less than what Jet resells it for. Try GM P/N 3053190.

Good luck!