'92 Supra 7MGTE overheating - need help pls.

[liona]

Greetings! I'm a newcomer in this forum.
I've had this supra for over six years without any major problems, until last week when the engine became very hot (almost approaching the red mark if I did not stop to cool down), even with all fans working ok.
The following day, I filled the radiator full and the coolant reservoir to proper level , drove five miles and the temperature shot back up to approaching red mark again. When I opened the hood, the reservoir was overflowing with very hot bubbling coolant.
I am definitely losing coolant, almost emptying the radiator. I do'nt see any obvious line leak or hose break. In checking the oil dipstick, it did not seem to have any "watery or bubbly" coolant like substance or anything other than engine oil (my oil have just been changed recently, so it was still clear). I also thought that the level on the dipstick should have substantially gone up, if the coolant got into the oil chamber considering the large volume of coolant lost.
Could it be problem with water pump, thermostat or whatever other malfunction causing engine to overheat. The coolant appears to be flowing to the radiator well, but I am not sure if it is coming or circulating well back to the engine. How do I check if the water pump is bad?
I only know very little about engine stuff. I would appreciate very much any help or advice. I've only got 91,000 actual mileage, as I only have a short home to work commute. THANKS MUCH IN ADVANCE FOR YOUR HELP!

[dcrusupra]

Sounds like a blown head gasket. You should do a compression check also.

[ddmcse]

smell the exhaust ....a little sweet ?
i'd pull the oxygen sensor thats bolted into the turbo elbow and see if it's coated with a white layer of stuff.

[liona]

Thanks for your reply!
'just trying to understand more about blown head gasket... is that what is causing the coolant to get into the engine and mix with oil?
Should I also look into or replace the water pump or thermostat?

[Dejvid1785]

Yes thats a blown head gasket!! I should know about those symptoms.

[kewlcoconut]

sounds like the symptoms i had when my HG went. i didnt have the mixture of oil and coolant. instead i had the mixture of coolant and exhaust gases. exhaust gases push the coolant into the overflow bottle. and in extreme cases they push it out and it overflows like crazy. mine did the same thing. 2 days later i was driving and the temp gauge shot right up, so i parked it and let it sit all day. started it up again, and white smoke as far as the eye can see. i think i covered my street with smoke. it was insane.....seriously, get it checked out. mine was so bad it warped the head. cost a lot to fix.

[Isphius]

It could also be a beat thermostat. mine did that not to long ago. But if there is oil in the coolant the head gasket isnt ok either

[SupraRed]

I'd take a quick look at the Radiator if you already havent, I know the Rads on the Supra can get clogged by all sorts of things and it has been a common occurance.