trans am wont stop overheating@! PLEASE HELP - Third Generation F-Body Message Boards

tweakhat · 09-26-2009, 10:52 AM

hey i have a 86 TA that has a new radiator and fan. but the water still boils in the overflow tank. could the quarter sized hole in the over flow tank be the problem? i have it duct taped. the dash doesnt say its overheating. but the water is boiling.

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305sbc · 09-26-2009, 11:21 AM

Better double check your coolant temp sensors, and check to make sure your radiator/pressure cap is holding proper pressure.

tweakhat · 09-26-2009, 11:24 AM

the shop i had it in installed a new temp sensor. i just converted it to carb too. the cap is pretty tight.

TADailyDriver · 09-26-2009, 11:43 AM

Quote:

Originally Posted by tweakhat

the shop i had it in installed a new temp sensor. i just converted it to carb too. the cap is pretty tight.

Just cause the cap is tight doesnt mean is holding pressure. pull the cap on the radiator and put a pressure tester to it. If it doesnt hold a consistent 15lbs for 5 minutes its junk. The gasket under the cap may be bad. If and when you buy a new one, buy a vented cap just in case your car does start to overheat. Had the same problem with my Trans Am right after my engine swap. Also what degree thermostat you running? 180, 195, 160??? Also, what size raditator did you put in? single core? Dual Core? And is your engine stock or build and bored??

tweakhat · 09-26-2009, 11:58 AM

that may be the problem. the same cap came on the car in 86. prolly worn out. ill check that out. im not sure what temp he put in the car but he wired the fans to come on with the ignition, which i wasnt a fan of but my wiring seems to be crossed a few places so i cant get the relay to work right without blowing fuses. so i guess the way he did it is best until i can buy a new wiring harness and convert it back to tpi, im not sure about the radiator. i got a aluminum one from advanced auto parts for 91 dollars. and its a pretty stock 305.

transam85dudeman · 10-12-2009, 06:36 PM

Quote:

Originally Posted by tweakhat

that may be the problem. the same cap came on the car in 86. probably worn out. ill check that out. im not sure what temp he put in the car but he wired the fans to come on with the ignition, which i wasnt a fan of but my wiring seems to be crossed a few places so i cant get the relay to work right without blowing fuses. so i guess the way he did it is best until i can buy a new wiring harness and convert it back to tpi, im not sure about the radiator. i got a aluminum one from advanced auto parts for 91 dollars. and its a pretty stock 305.

i got an ALUMINUM RADIATOR FROM KRAGEN. theyre tight. 110 bucks. ANyways with a new radiator requires a new cap. 16lbs vented is the cap needed. DONT DUCT TAPE. go to http://www.google.com/url?q=http://w...ZmpYvJ5HKAtAuw get a new coolant overflow tank if you got a hole. and make sure you bleed the radiator too. to bleed. run the engine from cold with the cap off. allow the engine to warm up while continually pouring fluid in the radiator to where the water meets the cap hole. and continue to fill and squeeze the top radiator hose to get air out and to feel if its hot. when the top hose gets hot thats when the engine's t-stat opened and is letting coolant through the engine. stock t-stat is 195*, i run 180*, dont run 160* unless you reprogram your chip otherwise the ecm will stay in open loop mode.. And also when you make up the coolant. it has to be exactly 50% coolant-50% water. I dilute the coolant with distilled water in a big tupaware plastic bin before adding to the radiator, and add the rest of the diluted coolant to the coolant bottles for backup. Because there are no salts calcium, chlorine, etc in the distilled water, it allows the coolant to be used more efficiently