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replaced head gasket still overheating

1506 Views 16 Replies 10 Participants Last post by  suprra_girl
Hey guys, i recently puchased a non-turbo 87 supra with a bhg. I replaced the hg and had the head and everything checked before replacing it. For the past two days i have been trying to figure out why it is still overheating. I got a new thermo, checked the water pump, even put an electric fan on. Although it did seem like it took longer to start overheating when i put the electric fan on. Is it possible for the radiator cap to be causing this? It's not leaking out the radiator cap but maybe it could still be bad. I have fixed every single little leak on the car in this process and there are no leaks anywhere. Any info or opinions would be greatly appreciated! Also how do i reset the ecu?
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Why did you put on an electric fan instead of the stock fan?

You can reset the ecu by removing the ecu fuse in the fuse box near the battery.
Just eleminating possible problems for overheating. I'm putting the stock fan back on since that was not the problem. Still wandering if it could be the radiator cap.
Nothing wrong with the stock fan when it's working properly.
never said there was anything wrong with the stock fan. Just going through everything that could possibly be wrong and replacing. Trial and error.
did you even burp/bleed the cooling system????

aite, peace.
yeah, i burped the system multipule times. Even jacked the front end of the car up to make sure i got all the air out of the system. Gonna go bye a cap later i guess and try that to see what happens.
Sounds like you need to have the rad., cleaned out their must be a folw restriction in there. Have it serviced at radiator shop. $50.00 maybe!!!
Fill the rad. with water, while the engine is cold. Crank it and let it idle. You should be able to feel the current flowing in the radiator, ..especially when the thermostat starts opening.

Its got be something like that. Does it look like alot of corrosion down in there? Also, its possible for a rad. hose to swell on the inside, and restrict the coolant, even if the hose looks good on the outside. So, you might look at that too.
I checked the bottom hose when the engine was running and pretty warm and i was still able to hold onto it with my hand cause it wasn't very hot. I took it off and checked it and it wasn't clogged or anything. There is a lot of what looks like rust stains inside the hose. I'm gonna replace that hose, the cap, and flush the radiator tomorow and then we will see what happens.
Are you loosing coolant when it starts to overheat? Try the napa test kit to see if your head gasket job was done right or is it still leaking again.
yes, it loses fluid when it overheats out the overflow. Did the test and it not blown. The head was not craked or warped either cause i took it to a shop and had it checked. My last guess is that it's got to be the radiator. Went to the junkyards to day but no luck. Found three 7m's that the motor's had not been touched but the only thing missing was the radiator in all of them! Is this a common problem with supras?
anybody around ky got a radiator for sale? It's the last thing it could be unless anyone has any ideas?
Kinked lower rad hose? They have that weird bend in them and not a lot of space. Did you clean out the crap between the ac condensor and the radiator? That always is the first thing I check for if I'm running a little hot.
hmm, not sure what ur talking about beteween the ac condensor and the radiator but i will take a look at that when i get up. I took the bottom hose off and put it on and it's not kinked. It doesn't seem like the bottom hose is getting very hot though. I replaced a few sensors and the thermo, it can idle all day long without overheating but about 5 minutes of driving and it overheats. I shut it off way before it over heats though cause that headgasket wasn't the most pleasant repair in the world. and i keep retesting it after i run it to make sure i haven't blown it.
How about your upper radiator hose, I had a problem with mine collapsing after the car warmed up...
so it would seem that at 600rpm it can idle all day but as soon as you drive i.e give it more rpms = overheating, that would suggest that the radiator is blocked or between the a/c radiator & water radiator is full of leaves etc.

You may end up getting another radiator from a junkyard but be in the same position. Just take it to a shop and they can power flush it for you.

When you drive it does it overheat instantly? What is cooling like on the highway cruising? Does it overheat when you come to a stop?

edit: also being that the lower rad hose isn't getting very hot would suggest that the hot water is not entering the radiator? Could be a faulty thermostat?
Try another one or remove it completely "temporarily"
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