Got the car running, now over heated and other problems.

I

iDriftYou

New Member
Oct 10, 2010
40
0
0
SoCal/805
Well I recently did a full swap on my car, complete 7mgte with all new internal HKS MHG, ARP studs. The first time we torqued the head down, we had a stuck valve so we had to pull the head again. Then I got a complete head job done, new valves, seals, etc. I cleaned the MHG with acetone and used copper spray, waited until it got tacky and put the head on and torqued to 95 ft lbs. This time the car ran perfect, everything sounds great. I had a Mizu aluminum radiator in it but when the cooling system built pressure it started leaking from the core so for now, I put the stock rad in, also took the POS autozone thermostat out. First drive, I drove it about 30 miles and it was completely fine on the freeway. When I got off the freeway, drove for about 600 feet, all of a sudden my temp starts to go up, coolant is boiling over shooting out the overflow. I turn the car off before it got to the red and let it chill. Poured coolant in the and bleed the system. Drove it back, no overheating problems at all. But when I got back, I did notice my intercooler was wet, seems like some coolant was spat out through the overflow. I drive my car almost everyday since that incident, it been about two weeks now and it's been fine. When I went to check the coolant after a drive, it seemed like there was no pressure in the cooling system. So I'm waiting for my new radiator to come in but what are the odds Ive got a BHG? Also, when under boost my car has a loud squeaking sound, I was thinking it might be a boost leak but can it be anything else? The turbo was rebuilt two years ago and has about 10k miles.

I know thats a long read but thanks for reading and thanks for all your replies!
 
metaphysico

metaphysico

Mad Scientist
Jan 2, 2008
428
0
0
44
Gainesville, Georgia
Don't use copper spray on the head gasket http://www.supramania.com/forums/sh...ay-Sealer-on-a-MHG-...Might-Want-to-Read-This

So highly likely the head gasket is leaking. Under boost is it a squeak or a squeal, what bov do you have aftermarket one? It could be bad and blowing off early, or could be boost leak. For coolant coming out into the expansion tank and it not holding pressure you probably just need a radiator cap, this is so often overlooked. As for overheating if your cap is bad it can let coolant into the reservoir but may not be able to pull it back into the radiator so after a few heating cycles the coolant will be low in the radiator.

But if you were driving and it was find but then slowing down or stopping makes it overheat check your fan setup, if its a fan with clutch make sure the clutch is holding, if its an electric setup make sure it comes on and make sure its pushing air in the correct direction, air flows from front of car toward engine.
 
supraguy@aol

supraguy@aol

Well-Known Member
Dec 30, 2005
4,236
37
48
Atlanta
Yes. The thermostat is designed to hold coolant in the radiator long enough to allow the heat to be transferred to the rad, and thus to the airflow. If it flows straight through with being allowed to "pause" in the radiator, then no heat gets radiated, thus sending hot coolant back into the block, and this becomes a losing cycle. At highway speed, the coolant may get enough airflow at speed to arrest this upward temp spiral, but at low speed(airflow), it can't keep up.
 
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