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Discussion Starter · #1 ·
Hi Everyone

So I've been having this issue for a while now.

My car(especially on track) shows very high temps after like 2 laps, up to 125+ degrees celcius on the oil and 120 on the water (aftermarket defi gauge). water temp also goes to red on stock gauge at track, not on normal roads (but in daily driving i can easily reach temps of 105-110dc on water and oil and if i dont manage it even higher)

What I have a 91 jdm na swopped with a full rear clip jdm gen 3, downpipe wrapped in heatwrap and aftermarket exhaust, oil cooler, 3core radiator, ats top mount intercooler, stock boost(except for the bit added by the mods). And a flown and ported head.

COOLANT is blead properly.

so issues I have that might be or not be related is there is some oil on the intake side of the turbo.
Compression test show as normal, I did how ever have one anomally where compresion was way down when testing engine hot?
Leakdown test showed nothing.

So I'm at wits end, any suggestions?

Thanks in advance
 

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I had the same symptoms as you and my root-cause required a rebuild. But first, you should eliminate the smaller possibilities like replacing the thermostat. It's probably not the issue as they usually don't fail in the way you are describing, but they are very inexpensive.

Are you consuming any coolant?
 

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Do the temps slowly climb, or does it run OK for a period of time and then suddenly over heat? In my experience the later is often a head gasket issue.
 
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Discussion Starter · #6 ·
hi guys thanks for the replies! I forgot to mention it has a brand new sard filler cap and thermo as well, swopped out the stock ones recently to those to see if it makes a difference. @Alex W it does run fine for a time and then it climbs like you say, do you think headgasket or possibly the guy that polished the head might have "hit" something?

edit yes i do consume small amounts of coolants, but not always
 

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hi guys thanks for the replies! I forgot to mention it has a brand new sard filler cap and thermo as well, swopped out the stock ones recently to those to see if it makes a difference. @Alex W it does run fine for a time and then it climbs like you say, do you think headgasket or possibly the guy that polished the head might have "hit" something?

edit yes i do consume small amounts of coolants, but not always
I had a very similar issue. I eventually swapped in a motor and then took mine apart. There were two thing we narrowed it down to 1 head gasket was bleeding coolant in the combustion chamber because the head had some rot. From what we don't exactly know. Previous owner had bad grounds was a guess. And two a failed or failing water pump. All steming from a boiling over issue or the motor not cooling because of a one time thermostat not opening


Take the thermostat out and drive the car under no boost . See how long it takes to over heat. But if you are eating or losing coolant then you have a leak or a bad head gasket.


Get a look inside and check out the pistons if they look super clean you probably need a head gasket.
 

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Your last Hail Mary is that there could be radiator blockage. You’d have to remove the radiator and have it cleaned and pressure tested. I highly doubt that is the issue.

It’s possible that the water pump is failing, however, this is very unlikely. When they fail they usually leak externally.

it’s probably a leaking head gasket. In my situation, combustion gases would leak into cooling system causing it to pressurize and get air pockets. Then it would overheat. It only took 1 3rd gear run for my car to overheat.
 

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I know owners like to avoid the inevitable conclusion, but this sure looks like a good bet for a head gasket issue to me.
 

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I know owners like to avoid the inevitable conclusion, but this sure looks like a good bet for a head gasket issue to me.
I'm going with this too. If the cap is good and you are using coolant then it does point to a head gasket.

hi guys thanks for the replies! I forgot to mention it has a brand new sard filler cap and thermo as well, swopped out the stock ones recently to those to see if it makes a difference. @Alex W it does run fine for a time and then it climbs like you say, do you think headgasket or possibly the guy that polished the head might have "hit" something?

edit yes i do consume small amounts of coolants, but not always
When you start the engine from cold with the filler cap off, does it bubble?
 

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Discussion Starter · #11 ·
i agree, now do i pull motor and do rings while im at it, or just pull head get it skimmed again.

@GDII no bubbling mate none of the other "obvious" headgasket issues
 

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Do a combustion gas test on the coolant, that'd tell you quickly if you have a leaking headgasket. You mention getting the head skimmed again like it has been done before, is it possible that the block surface is bad?

If the bores aren't completely smooth and you can see the cross hatching I wouldn't rering it. If you can do a leakdown test it'll give you an idea of how worn your bores and rings are (you might even find your headgasket leak too.)
 
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