I have a 91 Camaro RS with a 305 thats being bored .030 over and my radiator has a little crack on the plastic part of the radiator but my car get really hot during the day. it gets up to like 240-255. and my fan is setup to turn on when the car is started. i just recently replace the thermastat with a 160 and flushed the radiator. im just worried why the camaro gets that hot on highway (about 220) and city traffic (240-255) when i also own a 92 pontiac firebird convertible with a 305 automatic it also has a 160 thermastat and the fans kick on at about 220 but temp stay at 180-195 so the fans dont kick on unless i turn on the ac. is thier something wrong with the camaro. is it the radiator because of the crack. What anout the Waterpump? maybe my heads? any answer would help from you guys. Thanks
Martin
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and i live in arizona and the temp right now is at about 90s im worried when we hit 100s+

 

Get the radiator fixed. Rad shops should be able to do that fairly easily.

 

My 88 305 TBI had the combination plastic / metal radiator. The plastic was a functional part, by that I mean under pressure. I developed a crack also, along the top. Lost very little coolant, but overheated rapidly.

Guess what? That crack = loss of pressure, which reduces the boiling point of the coolant. You are boiling your coolant. Get the radiator fixed or replaced.

 

Check that air is running ok through the radiator, check if there is some dirty between the radiator and the A/c condenser, keep checking coolant level, check the fan work, and get that crack fixed to discard that cause, if the problem persist write again to think in another cause ok.
B-Rod.

 

well i just order a radiator. and as soon as i get a new radiator ill let you guys now whats going on. the fan works all the time when the car is on and when i run the car for a while and let the temperature go up 220+ and turn off the car i can hear the hissing sound from the radiator but its not steaming or the coolant overflow is full with coolant. but i cross my fingers that its the radiator. Thanks guys
Martin

 

how would i know if the car has a reverse flow water pump without taking the waterpump out?
Martin

 

Is it an electric fan? I am not up on my 305's, but the 350 TPI fan unless programmed different only runs at the temps you listed for the convertable. If the fans are running at start up and it has not been programmed that way, it is usually a sign that the car is in limp home mode. This mode may ar may not supply the correct fuel mixture to your engine. If it is running the engine leam it will run hot.

 

how would i know if its in limp home mode? that car use to run rich without a cat and a bad o2 sensor and i installed a high flow cat and a new o2 sensor and the car passed emmission without anyproblems. i dont get the best gas milage due to the engine being bored and rebuild and i dont now whats in the engine internally. but the car has some serious HP TQ on it. and it does have elictric fans but ill find out if the previouse owner set that up on purpose.
Martin

 

I had new tanks put on my radiator several years ago, the entire cost of the job including labor was less than the cost of a new radiator alone. Never had a problem with it after that.

 

i bought a new brass tank radiator. and added 50/50 coolant and water with a bottle of purple ice and i notice the car only gets hot when i have the ac on but if i turn the ac off the engine starts to cool of little by little. is there a problem why it overheats with the ac on?