I have a 89 supra turbo and last weekend I was heading back home when I notice driving on the freeway, my car started to overheat even at 65-80 mph. I have a koyo aluminum radiator and I converted the belt driven fan to an electric fan. Please help! Thanks
overheats when driving long distances and coolant the overflows tank.
- Thread starter nick_mk3
- Start date
Definatly check the thermostat...and it may sound simple, but check the radiator cap too! Make sure you have the correct pressure rated cap!
JustAnotherVictim
Supramania Contributor
Overheating at high speeds can be a few things. If you have already inspected for the obvious like hoses being clogged, Supra eating coolant ect., here are a few things to consider.
When you are on the highway and it's overheating, does turning on the heater help it come down? If so, your water pump is not the cluprit.
When you slow down from highway speeds, does the temperature get better or worse? If it gets better then you might want to check your koyo.
Also those fans might be the culprit, The stock fan when the clutch is in good condition is a very good cooler, and should be more than enough for your needs. But then again... One more thing on a pulley that much less power... Reliability and Power. They are inversely proportional.
Whatever you do, fix it now. Overheating leads to a warped head and a BHG.
When you are on the highway and it's overheating, does turning on the heater help it come down? If so, your water pump is not the cluprit.
When you slow down from highway speeds, does the temperature get better or worse? If it gets better then you might want to check your koyo.
Also those fans might be the culprit, The stock fan when the clutch is in good condition is a very good cooler, and should be more than enough for your needs. But then again... One more thing on a pulley that much less power... Reliability and Power. They are inversely proportional.
Whatever you do, fix it now. Overheating leads to a warped head and a BHG.
Fans play very little part in high speed cooling.
It's usually a blocked Rad/AC condensor or a missing plastics as air will take the path of least resistance and bypass the radiator if there's an easier way.
My car runs +5c with just the 3 bolts under the rad support missing from the undertray and +10c with the undertray off at highway speeds, my cooling system is perfect so imagine what that will do with a 15+ year old rad half blocked.
It's usually a blocked Rad/AC condensor or a missing plastics as air will take the path of least resistance and bypass the radiator if there's an easier way.
My car runs +5c with just the 3 bolts under the rad support missing from the undertray and +10c with the undertray off at highway speeds, my cooling system is perfect so imagine what that will do with a 15+ year old rad half blocked.
IJ. said:
I had the same symptoms and it turned out to be a blocked rad as well, but when he car was spitting coolant, it was a BHG. This guy doesn't have the stock rad though, he has a Koyo.
AC Condensor could be fullOcrap mine was 
That and missing plastics could cause it to run hot at speed but it shouldn't be pukking into the recovery tank...
That and missing plastics could cause it to run hot at speed but it shouldn't be pukking into the recovery tank...
did you perheps do a prestone radiator flush when you installed the Koyo?
if not... and your rad cap is functioning properly, I would take it to a mechanic and check for exhaust fumes in your cooling system.
if not... and your rad cap is functioning properly, I would take it to a mechanic and check for exhaust fumes in your cooling system.
yes, I am missing the under cover, but it didn't overheat before. Also, I just installed a silencer to my muffler that the outlet hole is only about 1.5 inch. Would that cause my overheating problem. The coolant spitting out only happens for long distances. Is it a bhg? You guys think changing my coolant could help? Any other tests I could do to?
you're increased exhaust back pressure probably exasperated your BHG. Like I said, do an exhaust gas check.
check and clean your battery terminals. is your battery fully charged?nick_mk3 said:
If everything checks out OK, your starter is going bad.
AND? No fumes?nick_mk3 said:
Did you do anything to your cooling system before, like a system flush?
How is your radiator cap?
Why do I have to repeat my questions?