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Discussion Starter · #1 ·
I took my supra to the mechanic and he preformed a pressure test. He said the head gasket hasn't blown yet, but it's not in perfect shape. He put some stuff in the coolant to try and seal the gasket. After every drive I check the coolant overflow tank and find more and more coolant in it. I also see air bubbles in the overflow. The pressure in my coolant system is too high. I use a turkey baster to take the coolant from the overflow tank and dump it back into my radiator (ghetto I know, but it's all I can do). The car only over heated once on the highway after high speeds. The coolant probably poured out from the over flow tank do to high pressure. I see little amounts of white smoke from my exhaust sometimes, but it's not very thick, so it might be just condensation. So my question to you guys is, am I ruining my engine by still driving it? The mechanic knows what he is talking about so I don't think this is a radiator cap problem, or regular coolant leak from the lines. However, the car has not been through a block test yet. I did a compression test and got these results:

cyl 1: 170
cyl 2: 170
cyl 3: 170
cyl 4: 168
cyl 5: 160
cyl 6: 168

Are those numbers abnormal? They are high compared to the reccommended 156 psi . But there isn't a 14 psi difference between any of the cylinders. Should this problem be fixed ASAP? Thanks guys..

Tanner
 

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Yes It should be repaired since the exhaust gas in the coolant causes it to become acidic. You will cause damage to your block, head, and radiator. At the very least it will make it more difficult to replace the HG as the block deck and head will corrode.
If you must run it like that for a while I would change the coolant very frequently.
Good luck.
 

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re-torque the headgasket..........what have you got to loose if you're gonna park the car anyways?

i knew mine was going, and did the re-torque one night, and kept driving. 1 year later, ripped out the engine to swap, and just out of curiuosity ripped the head off to check the hg, and sure enough, cylinders 1 and 6 were shot, but number six was completely dead, the bore was all rusted too.......but i never leaked coolant, it was amazing.
 
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Discussion Starter · #5 ·
Well, I drove my car to work today with no problems. I even checked everything out before I went inside. I came back out a hour later and there was coolant EVERYWHERE. I popped the hood and looked around. The radiator hose going from the radiator to the thermostat housing had a six inch tear in it. I think the pressure built up so much it blew the hose in half. I really didn't want to buy a new hose and more coolant to get the car running again, so I had it towed to my mechanic, which was only five miles away. I think I'm just going to replace the f'ing HG. I've already put 400 dollars into this car, so now I might as well dump another grand into it. If I have the mechanic put a stock HG in and APR bolts, what should the bolts be torqued to? Would the stock HG bolts be fine if they were torqued more than 50 lbs? I don't want to pay tons of money on this job and then have the HG blow again. Thanks for the help guys..

Tanner
 

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i would say just buy a cometic and arps. do the job yourself and have a friend help you. didnt take me to long but the machine work set me back about 1 1/2 weeks. but i ordered my shit in advance since i was planning on doing it.
if anything torque the bolts to 76-80ftlbs. NOT 56!
 

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haha ive been running my supra for 7000 miles with a BHG and a mean ass rod knock and its still ticking. Supras are bulletproof
 

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A Happy Dad
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Do it yourself, please. It'll run $200-250 max and 4 to 8 hours unless your block is already screwed
 
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Discussion Starter · #10 ·
Do you guys think my engine is already screwed? I only drove it for three days while the car was in this condition, but only God knows how long the previous owner drove the car like this. What do you guys think about those compression numbers? I would fix the HG on my own, but I don't have the time, or the proper tools. Hence why I took it to the mechanic.
 

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compare your oil pressure readings with what they are supposed to be. if they are a lot lower, and you have the proper amount of oil with the correct grade, then yeah, your bottom end is shot, but u should be able to hear the rod knock if it was that bad
 
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Discussion Starter · #12 ·
di_rosa said:
compare your oil pressure readings with what they are supposed to be. if they are a lot lower, and you have the proper amount of oil with the correct grade, then yeah, your bottom end is shot, but u should be able to hear the rod knock if it was that bad
The oil pressure gauge shows the right amount of pressure. The mechanic told me he heard a slight engine noise, however, which is why he put 20w-50 oil in it. I could not hear any rod knock while driving the car. Should I just buy another engine? I found some on ebay for as low as $800 plus shipping. Wouldn't it be easier for the mechanic to put a new HG on an engine that is already out of the car? If it was easier, he wouldn't charge as much for labor. So what do you think guys? Should I fix the HG and keep my 127k mile engine? I wish I could get a MHG in there so I could boost more, but the mechanic would rape me for money....
 

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A BHG will eat the S out of anything aluminum. My Sup (that was given to me) was driven quite a bit with a BHG. Virtually anything aluminum was seriously eroded. The head had huge pits in it (especially around the water jackets), the thermostat housing was shot & would not seal, the oil filter housing was eroded so bad it looked like it wouldn’t seal. The radiator looked like it was dipped in acid and dissolved from the inside out. I wouldn’t drive it, but that’s just me.

Dale H
87T
 

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i drove mine for a while by just torqing the head dow again. those compression numbers are pretty damn good dude!! you are ok if there within like 20% up to 30%. the first dyno that i did i put down 389rwhp with the cylinder compression at:

140
155
175
175
179
170

i had two dead cylinders and it still ran great! it had a slight skip at idle, but i ran it this way for about 6 months with 18-20 psi on an upgraded ct. the motors are strong, the hg's weak. as long as it doesnt over heat, and you keep coolent in it youll be fine!

however, if you have the means or the money to get it fixed, do it asap and save yourself the pain of over heating and hurting something more serious! keep your eyes on the coolent temp!
 
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Discussion Starter · #15 ·
DAVID SWEARINGEN said:
i drove mine for a while by just torqing the head dow again. those compression numbers are pretty damn good dude!! you are ok if there within like 20% up to 30%. the first dyno that i did i put down 389rwhp with the cylinder compression at:

140
155
175
175
179
170

i had two dead cylinders and it still ran great! it had a slight skip at idle, but i ran it this way for about 6 months with 18-20 psi on an upgraded ct. the motors are strong, the hg's weak. as long as it doesnt over heat, and you keep coolent in it youll be fine!

however, if you have the means or the money to get it fixed, do it asap and save yourself the pain of over heating and hurting something more serious! keep your eyes on the coolent temp!

Well, my supra is at the shop right now. I'm just debating whether to drop in a new engine or not. I can get a new engine for 1 grand, versus paying $1300 for the new HG. But then the new engine would need a new HG eventually. I'm stuck on what to do...
 

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change the head gasket your self its easy just remember where everything goes. mine only cost me 200 dollars it runs perfect. arp studs 100 and a greddy metal head gasket from a close friend for 100.
 
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Discussion Starter · #17 ·
mattsmall said:
change the head gasket your self its easy just remember where everything goes. mine only cost me 200 dollars it runs perfect. arp studs 100 and a greddy metal head gasket from a close friend for 100.
I don't have the time or tools. Plus, I don't know this car well enough.

Another question for you all:
How many pounds of boost could I safely run with the stock HG and APR bolts or stock bolts torqued to the proper specs?
 

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Stormcock approves
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The question is are you sure you have a BHG? If you had exhaust gas making its way into your coolant and building enough pressure to blow a hose open, I would think your compression numbers would reflect it. And if you did have low compression on a cylinder, there are more causes than just BHG to consider.
 
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Discussion Starter · #19 ·
Shlongor said:
The question is are you sure you have a BHG? If you had exhaust gas making its way into your coolant and building enough pressure to blow a hose open, I would think your compression numbers would reflect it. And if you did have low compression on a cylinder, there are more causes than just BHG to consider.
By the time I did the compression test, the engine wasnt warm any more. Although I drove it for 10 minutes before starting. Maybe this messed up my compression results. I tried have a new radiator, radiator cap, thermostat, and water pump. The overflow tank is filled with coolant to the brim after most drives. I can see air bubbles in the coolant, and I can hear gurgling noises from the engine bay. WTF is going on?
 

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A Dyno never won a race..
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that water will cut your head like a lazer. Fix it now. The longer you run it, the worse chance the head will be crap and cant be welded or fixed.
 
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