Help!!!!

[430hpToy]

I'm lost! I think my radiator is toast but not sure. Here's the problem... After the car has been running for a while and under some kind of load, it starts to overheat. If I crank the heat, it sometimes cools down, when the temp. does drop it drops instantly, almost like there's a big air pocket or somethig, if it doesn't drop, well then it gets really pissed and starts steaming and the radiator cap starts making noises and it starts spitting water out of the overflow.

Here's what I've tried so far....

Changed the thermostat

Flushed the system added new coolent and water

Pulled the thermostat and ran without one

Pulled the main hose on the ignition side and ran water through to make sure everything was circulating correctly

Ran the car each time and still does the same thing!!!

[Piddy]

^ Mine does the exact opposite. My temp. goes WAY low. I'm going to have the coolant replaced this weekend... and hopefully that will do it. If not, I'm gonna replace the thermostat. What happened when you ran without the thermostat?

[430hpToy]

nothin much! did the same thing! i'm lost! someone says that it sounds like some kind of air lock

[JekylandHyde]

Are you sure you are properly bleeding the coolant system?
There is a specific procedure for doing it in the MR2.

Slight amounts of air in the system will cause over heating.

Is your gauge actualyl reading hot or is you radiator cap boiling/bubbling over?

[430hpToy]

Originally posted by JekylandHyde
Are you sure you are properly bleeding the coolant system?
There is a specific procedure for doing it in the MR2.

Slight amounts of air in the system will cause over heating.

Is your gauge actualyl reading hot or is you radiator cap boiling/bubbling over?

yea it's boiling and bubbling over! and no i'm not sure i'm bleeding it correctly! i've tried everything though, and it's driving me insane!

[Piddy]

You should look into buying the Big Green Book from Toyota. Helps a lot with maintainance. Or you can look online if it's a quick thing... but always helps if you can just take the book to your car.

http://www.mr2-tech.com/bgb/mechanic...mechanical.htm