LostMarine

So, pushing about 30PSI, 12-14* on E85, car decides to push coolant out of the overflow, every 2 runs. I did the combustion gas test and it came out just fine (fluid is below line right now as some spilled out after I removed and recapped radiator, but was at line when doing test). Friday we'll be doing compression test and re-tightening the L19 studs

Just cant see what else could push fluid out like this w/o being the gasket again, but it shouldnt be doing this at such "low" boost.

Anyone have any ideas/ probable causes?

yamahaSHO

When I pushed coolant through the head gasket on my STi, that standard block test kit found nothing. I had to use and electric CO tester to get it to register and when it did, it really did.

MorngWoodStewie

Intake manifold has a coolant port.

yamahaSHO

I haven't taken off/apart an S2000 intake manifold, but any coolant ports entering an intake path should not have a chance for pushing coolant.

MorngWoodStewie

Well that's quite a bit of psi... not unheard of just thinking if it's not the head it could be momentarily pushing through the IM gasket into the coolant system. Most higher rad caps are only 1.3 bars so would make sense why it's going one way (for now)

if u never re checked torque on head studs after heat cycle it probably should be verified anyways though. It's a pain and most say the hell with it. Additionally tho. If it did go by hg I doubt a re trq / check will fix it now. I would also figure a lifted head does not just go back to normal and test out good. Do the cr test n check for anymore symptoms starting to turn.

Just threw that out there because there physically is another route for pressure to go other then hg.

I'm assuming the block is built, meaning head was checked / and or decked and the block was checked or step decked. Was this engine just buttoned up and tuned recently? Are u running the OEM mls IM gasket or something else? Did u remove the IM during assembly or at any time and use the old oem gasket one? Was the trq un loaded properly on the IM, seems like a negligible thing but still.

yamahaSHO

For the boost to push its way through the intake manifold gasket to the coolant port, it'd show more issues in that area.

I'm betting head gasket.

LostMarine

Built/sleeved motor, head and deck were checked after previous headlift. Ive been beating the hell out of the car for about 6 months now. I decided to just go ahead and replace HG as its cheap insurance rather than trying to find some other mysterious issue.

Question now though, 1 guy i just met said benson informed him, he was popping HG, as his block was deforming under high heat. So i noticed now that IP uses different main studs as well. Could this be a similar issue, that the block is flexing?

MorngWoodStewie

Maybe JE pro seal hg might help then. If it was indeed hg.

If it's the block then I would figure either 1 it will never be right and or 2 it wouldn't last 6 months in the first place.

boostedf22c

Not if it's a an inlinepro sleeved block.

MorngWoodStewie

Good point

Didn't know it had happened b4...