Overheating!!!

[yellow88supra]

Ok guys, I have read every thread in this forum about overheating and BHGs.
None of the situations or sugestions are in my favor. I have rebuilt my 7mgte about 3 years ago and everything has been fine until now. I can start the car up and let it idle for 3 hours straight and no overheating issues. Then I can get in the car and drive it for 45 min. before the temp gauge starts to rise. It rises very slow. My heat quit working at the same time I started having these issues. When it overheats I cut the car off immediety. I check the overflow tank and there is steam coming from the hose, but no overflowing. I have replaced the Termastat, Flushed the radiator and motor, replaced the radiator cap w/a new stat 13lb. I have also done c02 test ( for exhaust gases in cooling system) and it come back ok. There is no coolant in the oil and no oil in the coolant. Not a hint of smoke coming out the exhaust. It isn't even leaking any coolant from anywhere including the overflow tank. This car runs great. Great power, Doesn't cut off even when it is overheating. Runs the same it has since the rebuild perfect and smooth.( w/the exception of the over heating and no heat) There has always been two wires that are broke off the thermastat housing and I never could find out what they are for but they have been like that since I received the car. Can anyone help me w/this problem, I am at a loss. I really don't want to pull this motor back out if I don't have to! Any and all help will be greatly appreciated. Please someone help me!! Thanks in advance Jesse,

 

[super supra dave]

im haven the same prob with my car. they day i got it running we had revd the shit out of it and made sure every thing was running right. was off a few degrees on the timeing like 2. got it out on the street and ajusted the cps and it ran alot better. so every thing is going fine and then i get on the highway and bam the temp starts going up. pull over nothing looks wrong, let it cool done then get back to home as safe as i can. start driven it on the street agen and dose fine under 45. but ill pull over just to check some othere ting and open my hood the manifould s glowing red. so i really dont know what its doing but now it dosent want to idel right. the othere day i started it up and i was pushing 5psi and i wasnt even at2000 rpms. i think she hates me.

 

[jose89t]

im haven the same prob with my car. they day i got it running we had revd the shit out of it and made sure every thing was running right. was off a few degrees on the timeing like 2. got it out on the street and ajusted the cps and it ran alot better. so every thing is going fine and then i get on the highway and bam the temp starts going up. pull over nothing looks wrong, let it cool done then get back to home as safe as i can. start driven it on the street agen and dose fine under 45. but ill pull over just to check some othere ting and open my hood the manifould s glowing red. so i really dont know what its doing but now it dosent want to idel right. the othere day i started it up and i was pushing 5psi and i wasnt even at2000 rpms. i think she hates me.

tha to me sound like your'e cat converter.do you have the stock exhust

also for yellow88supra
did you use the factory thermostat and fan cluctch. do you have the shroud
7mgte are very picky,do not buy these parts aftermarket !!!

 

[zachm611]

i would also get your radiator flow tested, even if it was flushed. this happend to be my problem, i went through every little thing i could think of and ended up changing the HG, while doing so it wasnt even bad, but i wanted to do it for piece of mind, title says car had 255k miles on it. changed the radiator and everything was smooth. also make sure you have the 10 blade fan, mine had some kinda redneck fix of a cut up fan i dont even know what it was from.

 

[yellow88supra]

Thanks guys for all your info. I figured out my overheating issue. My fan clutch went out about 6 months ago and instead of buying a oem one I got rid of the fan shroud and fan clutch. I replaced it w/a high output electric fan (This thing is a beast). I didn't have any problems because it was so cold here that I probably didn't even need one to begain with. As it started to warm up I started seeing the temp difference. I installed the fan per instructions and it caused this. Today I reversed the pularity of the fan and it fixed the problem immedietly. I feel like such a moron.


I am still having problems w/the following:

1) No heat, I just can't figure out why it isn't working. I checked the fuse box and there isn't any blown fuses. What can I check next?


2)There are 2 wires that hook up to the side of the thermastat housing. I believe one is green w/a stripe and the other is blue w/a stripe. Can anyone tell me what they are for and there importance for the cooling system?


Again Thanks to everyone for all your help, I hope I can help someone in the future w/parts or questions!

 

[Supraboy89]

Thanks guys for all your info. I figured out my overheating issue. My fan clutch went out about 6 months ago and instead of buying a oem one I got rid of the fan shroud and fan clutch. I replaced it w/a high output electric fan (This thing is a beast). I didn't have any problems because it was so cold here that I probably didn't even need one to begain with. As it started to warm up I started seeing the temp difference. I installed the fan per instructions and it caused this. Today I reversed the pularity of the fan and it fixed the problem immedietly. I feel like such a moron.


I am still having problems w/the following:

1) No heat, I just can't figure out why it isn't working. I checked the fuse box and there isn't any blown fuses. What can I check next?


2)There are 2 wires that hook up to the side of the thermastat housing. I believe one is green w/a stripe and the other is blue w/a stripe. Can anyone tell me what they are for and there importance for the cooling system?


Again Thanks to everyone for all your help, I hope I can help someone in the future w/parts or questions!

your no heat problem could be a bad heater control valve. it is mounted on the passenger side firewall. mine went bad and i had to manualy unplug the vaccume hose and plug it into the vaccume chamber on top of the heater control valve to open it. as for the 2 wires you are talkin about i believe they are for the temp sensor for the ecu.

 

[yellow88supra]

your no heat problem could be a bad heater control valve. it is mounted on the passenger side firewall. mine went bad and i had to manualy unplug the vaccume hose and plug it into the vaccume chamber on top of the heater control valve to open it. as for the 2 wires you are talkin about i believe they are for the temp sensor for the ecu.

That could explain why the car always runs real rich?

 

[suprahabsfan]

::bhg::