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Old 08-13-19, 10:32 AM   #1
SlowInFastOut
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Default A Page of Theory

Hopefully everyone is doing well!

I'm setting up this page as I am hoping someone has any other ideas of what my issues could be.

Let me give you guys the low down on the situation at hand.

Car: 2011 Sti Sedan
Engine: Element Tuning Pro Comp "race" block
Specs: closed deck ej257 case halves(billet inserts), element tuning forged h beam rods, Manely forged pistons 99.75, arp ca625+ 11mm headstuds(95ftlbs sequenced), 2017 sti nitrided crank new with forged bearings. Bc280 cams with ferea valvetrain and over sized valves. Cometic head gaskets with beautiful RA finish of the heads and block.

Cooling: Koyorad with 1.5 bar cap and 1.3 bar cap on expansion. Oem fans and shroud. Ets 3.5" core front mount intercooler

Boost: ets rotated kit with elh and a gen 2 GTX3576R 4inch inlet and tial 44mm mvr. GrimmSpeed EBCS.

Fueling: IAG v2 fuel rails on ID2000's, cobb flex fuel kit and radium twin pump hanger. Hardwired both with secondary being on a 12psi set hobbs switch. AN lines front to back. Aeromotive FPR set at 43.5 psi base pressure

Engine management: Cobb AP v3 flex-tuned for e75%. 500whp/445wtq @24.5psi

Now before we get into it i recently had to tear this thing apart and redo the head studs because i believe they originally came with arp2000s and they lifted and i started pushing coolant. Now it is on ca625+ studs and thicker cometic head gaskets. The heads have been touched up to flatten it out and checked for cracks as well.

Aside from another leakdown test and tear down to magnaflux the block, I have done all I could think of. It shows similar symptoms to a head gasket issue. Cold start has bubbles in the expansion tank, pressurized coolant hoses, excess coolant in the overflow. Filling overflow bottle under boost. The coolant doesnt completely return to the radiator after cooling(my main evidence to support the theory).

Things I have done are compression test(passed) Radiator/cooling system pressure test(holds just under cap release pressure for 5-10 min.
Boost leak test(passed at 24psi).

What I think is wrong:
I'm starting to get to the point where I think there may be some sort of crack or breach in the block opening up and slowly getting worse. The cometic install and arp ca625+ stud job came out beautiful and was brought up to 95 ftlbs of torque.
The problem that arose for me was overheating randomly on just daily driving and never above wastegate spring. I would let it cool off until the morning and pop the cap on the expansion tank to see it slightly down(about half inch) and the top section of the radiator was also low. So I look at the overflow and it was full to the cap. I fill it and bleed with a spill free funnel. Let it go through 5-6 fan cycles and cap it. Later in the week it happens again. The next morning i put the spill free funnel o the upper expansion tank and cold start it. Sure as it was there were small bubbles(simmering sized almost) floating up through the funnel. Whats weird is when i rev it up to see if it bleeds anymore is that more coolant gets sucked into the block when i do instead of it just gurgling from a spinning water pump.

Never have i had this issue before with any IAG blocks built or an outfront.

What are your thoughts? Im saving up for some case halves from IAG as we speak and just driving the car offboost and monitoring it.

Gonna swap over my internals to the new IAG case halves when we find a problem after magnafluxing this element tuning block.

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Old 08-22-19, 05:13 AM   #2
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Default Re: A Page of Theory

I was just going back in my own build thread reminiscing (lol) and saw all your posts from when you got the 35r on there. So I looked at your post history, and saw this unanswered.

What do your plugs look like?

I had a block (non subaru) develop a pin hole at the verrrrry top of the cylinder. It filled the cylinder with about a liter of coolant lol.
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Old 08-22-19, 11:15 AM   #3
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Default Re: A Page of Theory

worked on a few Toyota trucks that we kept doing headgaskets on...as we noticed repeat customers we reached out to Toyota as the machine shop saw 0 issues with the heads or blocks and comment was microscopic pinholes in head due to manufacturing defects where we received new heads and had no further returns for that issue...

also why not run a higher pressure radiator/expansion tank cap?

also with these metal headgaskets was advised to add copper gasket spray thoroughly before install...

Last edited by Jedi03; 08-22-19 at 11:17 AM. Reason: additional question
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Old Yesterday, 12:01 PM   #4
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Default Re: A Page of Theory

Quote:
Originally Posted by Joebie View Post
I was just going back in my own build thread reminiscing (lol) and saw all your posts from when you got the 35r on there. So I looked at your post history, and saw this unanswered.

What do your plugs look like?

I had a block (non subaru) develop a pin hole at the verrrrry top of the cylinder. It filled the cylinder with about a liter of coolant lol.
So my plugs are actually pretty solid. The gap opened up a tiny bit.( 2 thou ) but i closed them back up.

So now the coolant is the weird part of of this whole situation. All the coolant is accounted for. Its gets pushed out into the over flow mainly because the pocket of air is heating up, expanding, creating pressure and opening the expansion tank cap and going to the overflow. But if i were to say let it cool, open the expansion tank cap, take whats in the overflow and fill the system again im at the same exact level as where i originally filled and bled it.

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Old Yesterday, 12:03 PM   #5
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Default Re: A Page of Theory

Quote:
Originally Posted by Jedi03 View Post
worked on a few Toyota trucks that we kept doing headgaskets on...as we noticed repeat customers we reached out to Toyota as the machine shop saw 0 issues with the heads or blocks and comment was microscopic pinholes in head due to manufacturing defects where we received new heads and had no further returns for that issue...

also why not run a higher pressure radiator/expansion tank cap?

also with these metal headgaskets was advised to add copper gasket spray thoroughly before install...
We copper sprayed it, ran a 1.3 bar cap on the expansion and a 1.5 bar cap on the radiator. But there is definitely something going on that could potentially involve the block. I wish i had a gas content analyzer to see what type of gas is getting into the coolant system so it would point me in the right direction.

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Old Yesterday, 02:26 PM   #6
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Default Re: A Page of Theory

Quote:
Originally Posted by SlowInFastOut View Post
So my plugs are actually pretty solid. The gap opened up a tiny bit.( 2 thou ) but i closed them back up.

So now the coolant is the weird part of of this whole situation. All the coolant is accounted for. Its gets pushed out into the over flow mainly because the pocket of air is heating up, expanding, creating pressure and opening the expansion tank cap and going to the overflow. But if i were to say let it cool, open the expansion tank cap, take whats in the overflow and fill the system again im at the same exact level as where i originally filled and bled it.

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This isn't just the a bad or improper radiator cap not allowing the coolant to return?

Have to ask.
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Old Yesterday, 03:11 PM   #7
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Default Re: A Page of Theory

Quote:
Originally Posted by mheyman View Post
This isn't just the a bad or improper radiator cap not allowing the coolant to return?



Have to ask.
Correct. I've used multiple brand new oem caps for both expansion tank and radiator. To be exact i have used 4 pairs. Then i went with higher pressure ones to make sure my assumptions of pressurization was correct.

After cooldown over night it SOMETIMES may pull a minimal amount of coolant back into the system. Only once have i seen it draw all of what was pushed out back in. Til this day i can not duplicate it.

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Old Today, 10:48 AM   #8
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Default Re: A Page of Theory

I think quite a number of owners have reversed the caps from top and bottom tank and had similar issues. Head gaskets not sealing is an issue sometimes too. 2L heads often crack, and though I've never head of them loosing coolant from it, I'm sure it is possible. Never heard of this in a 2.5l engine.
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Old Today, 01:28 PM   #9
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Default Re: A Page of Theory

Quote:
Originally Posted by mheyman View Post
I think quite a number of owners have reversed the caps from top and bottom tank and had similar issues. Head gaskets not sealing is an issue sometimes too. 2L heads often crack, and though I've never head of them loosing coolant from it, I'm sure it is possible. Never heard of this in a 2.5l engine.
I've never mistaken a cap on these things. The expansion tank with the higher position has the lower pressure (1.1 bar) cap on it. The radiator hasthe 1.3 bar cap on it.

The long block itself is less than 10k miles old and are brand new subaru oem case halves inserted with billet closed deck inserts with brand new 2018 heads.

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