88 Supra Overheats !!

jsesky · 09-16-2009, 03:34 AM

Okay so I need some help and input. I have an '88 Supra 7M-GE. It is in great shape and is fun to drive. However, it overheats and I can't figure out why.

I first tried the simple stuff and had Toyota change the thermostat and the radiator cap. This did not solve the problem. I then had the radiator flushed out and refilled. This did not solve the problem.

There were no visible coolant leaks but you could smell antifreeze every time you started the car and drove it around. The coolant would boil over in the over spill tank and the radiator. The heat worked.

I then moved into the internal coolant leak possibilities beginning with the head gasket as this engine is FAMOUS for blowing them. However, the exhaust was clear and the oil had no milky residue or a cappuccino-like color. I still had the head changed anyway for good measure and the block was also inspected for cracking. All was clean. The fan spins fine, the water pump has not been taken out and inspected but the bearing does not feel lose and is quiet.

As long as there is coolant in the system the engine will not overheat but it goes through coolant very quickly.

I really am stumped on this one. I can only think of a few more things it could be. The coolant is obviously being burnt off somewhere but I don't know where. The car is 20 years old so I always go with gaskets and rubber seals being the problem first and am wondering if perhaps the Intake Manifold Gasket could be the culprit?

I'm starting to believe the radiator is bad though because the upper hose will not get hard despite driving it for quite some time and I can hear boiling in the radiator when the car is turned off. I plan on doing a pressure check tmrw.

What'dya think?

09-16-2009, 03:34 AM	#1
jsesky Stock Join Date: Sep 2009 Location: Scranton, PA Posts: 2	88 Supra Overheats !! Okay so I need some help and input. I have an '88 Supra 7M-GE. It is in great shape and is fun to drive. However, it overheats and I can't figure out why. I first tried the simple stuff and had Toyota change the thermostat and the radiator cap. This did not solve the problem. I then had the radiator flushed out and refilled. This did not solve the problem. There were no visible coolant leaks but you could smell antifreeze every time you started the car and drove it around. The coolant would boil over in the over spill tank and the radiator. The heat worked. I then moved into the internal coolant leak possibilities beginning with the head gasket as this engine is FAMOUS for blowing them. However, the exhaust was clear and the oil had no milky residue or a cappuccino-like color. I still had the head changed anyway for good measure and the block was also inspected for cracking. All was clean. The fan spins fine, the water pump has not been taken out and inspected but the bearing does not feel lose and is quiet. As long as there is coolant in the system the engine will not overheat but it goes through coolant very quickly. I really am stumped on this one. I can only think of a few more things it could be. The coolant is obviously being burnt off somewhere but I don't know where. The car is 20 years old so I always go with gaskets and rubber seals being the problem first and am wondering if perhaps the Intake Manifold Gasket could be the culprit? I'm starting to believe the radiator is bad though because the upper hose will not get hard despite driving it for quite some time and I can hear boiling in the radiator when the car is turned off. I plan on doing a pressure check tmrw. What'dya think?