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Old 11-13-2018, 07:22 AM   #1
Long Nguyen
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Join Date: May 2015
Location: Ho Chi Minh City, Vietnam
Default Help diagnose a possible blown head gasket problem

Short version:

With a perfect leak down test, can a blown head gasket be possible?

Long version:

EJ257 built long block: Darton sleeves, Forged pistons and rods, OEM crank, King bearings, GSC std valves, GSC guides, GSC springs, GSC cams, Ported & polished.

JE/Athena gaskets with Cooper fire rings from Outfront Motorsport.

ETS turbo kit with a 6466

KillerB Oil pan combo

The car was in the middle of tuning process. Mikey Botti worked out his magic and the car was making 500whp/410ftlb on pump 91 at 25-26psi.

I was super stocked with the result. All temps were good. Oil pressure held 85-75psi til 8100rpm. I was waiting for Mikey to continue on the E85 tune but the problem happened.

Since the PTE6466 does not use coolant I had to block off the coolant port. I used the provided silicone socks from ETS.

While cruising yesterday, the sock blocking the lower turbo coolant port blew. I lost most of the coolant.

At that moment the car was running fine. I only stopped the car when I glanced at the gauge and saw the 248 degree coolant temp. Popped the hood and found out the problem. Towed the car home.

However I was not sure if the 248 degree temp was correct since there might have been zero coolant in the crossover pipe at that moment.

I first thought nothing dramatic happened. I removed the little J shape coolant pipe and blocked the port with a screw. Refilled coolant and began the purging process.

The coolant bubbled so hard that it splashed all over the place. The coolant temp went up quick and I had to shut it off. I redid it a few times but same problems.

I thought the gaskets had been blown due to the “coolant loss issue” the other day. I pulled the motor out. While the engine was mounted on the stand I thought “why not do a leak down test?”

The leak down test surprisingly came out perfect. All cylinders came out 2-5% of leak (90psi base pressure)

Oil looked perfect, no milky syndrome. Coolant looked clear and no sign of oil contaminant.

Spark plugs came out with a nice color.

On the outside the engine looks totally clean, no leaks.

I scratched my head.

I thought a leak down test would diagnose a blown head gasket but not this case.

Please help me diagnose a possible head gasket problem!

Quick note: I did a hard break-in. Compression test came out 150psi on all cylinders (before the problem happened).

Thank you!
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Old 11-13-2018, 07:27 AM   #2
Long Nguyen
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Join Date: May 2015
Location: Ho Chi Minh City, Vietnam
Default



This is the leak down test.



This is how I blocked the coolant port after the problem happened. I thought this might have fixed it but NOT.



This is the car.



This silicone sock blew.
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Old 11-13-2018, 07:29 AM   #3
Long Nguyen
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Default

This is the video clip showing the purging process.

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Old 11-13-2018, 09:01 AM   #4
Charlie-III
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Silver Sleeper BK, 5MT

Default

Yes it's possible to have good compression and leakdown numbers and have a blown HG.
Keep in mind, the tests are about 200PSI or less, combustion pressure is many times higher.
Also, any Subaru HG I have seen blown did NOT have oil and coolant mixed in either system.
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Old 11-13-2018, 09:10 AM   #5
Long Nguyen
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Default

Quote:
Originally Posted by Charlie-III View Post
Yes it's possible to have good compression and leakdown numbers and have a blown HG.
Keep in mind, the tests are about 200PSI or less, combustion pressure is many times higher.
Also, any Subaru HG I have seen blown did NOT have oil and coolant mixed in either system.

Yeah I understand.

I was looking for a MIRACLE...
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Old 11-13-2018, 09:53 PM   #6
Humphrizzle
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vacuum fill coolant and use a more durable rubber cap for that coolant tube.
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Old 11-14-2018, 09:10 AM   #7
BADBERRY68
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Do you just change the head gasket or should make sure your heads and block are square and new head studs.
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Old 11-14-2018, 09:17 AM   #8
Long Nguyen
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Crack opened the engine today and so signs of head gasket problem. Everything looks perfectly sealed.

Maybe I over thought.

But I have never seen such a violent coolant purging like this:

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Old 11-14-2018, 10:05 AM   #9
Charlie-III
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Quote:
Originally Posted by BADBERRY68 View Post
Do you just change the head gasket or should make sure your heads and block are square and new head studs.
You should ALWAYS check the block and heads when doing a HG, especially turbo Subaru.
I have not had issues on NA, I have seen issues with a couple turbos.
As to reusing head bolts, I always do, but some say no.
If it was the 4th time or more bolting the heads on, I might swap them out.

To the OP, bad HG's I have seen usually look fine, they just leak.
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Old 11-14-2018, 02:24 PM   #10
BootsJunkie
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Just curious how many miles were on the motor? If very little, could explain no visible signs on the head/block/HG of leakage.


So if compression & leakdown's can't POSITIVELY identify a bad HG, and there won't necessarily be chocolate milk oil/coolant........ hell, even disassembling the motor to visually inspect HG's and mating surfaces can't even guarantee bad HG's....

Is there ANY 100% guaranteed test/sign/inspection that'll ID a bad HG?



This is going back to Charlie's "Nuts n Bolts" thread with the coolant pressure tester, I have one rented ATM and am going to perform the engine running test tonight *fingers crossed*
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Old 11-14-2018, 03:46 PM   #11
Charlie-III
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Silver Sleeper BK, 5MT

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Quote:
Originally Posted by BootsJunkie View Post
Just curious how many miles were on the motor? If very little, could explain no visible signs on the head/block/HG of leakage.


So if compression & leakdown's can't POSITIVELY identify a bad HG, and there won't necessarily be chocolate milk oil/coolant........ hell, even disassembling the motor to visually inspect HG's and mating surfaces can't even guarantee bad HG's....

Is there ANY 100% guaranteed test/sign/inspection that'll ID a bad HG?


This is going back to Charlie's "Nuts n Bolts" thread with the coolant pressure tester, I have one rented ATM and am going to perform the engine running test tonight *fingers crossed*
Mild blown HG, chemical/hydrocarbon test is best assuming no oil leaks into cooling.
Using a pressure tester (in my thread you mentioned) is pretty sure.
Ask me questions, here or in that thread. I have used the coolant pressure tester to identify bad HG's when most others don't.
Nope, never saw it as a diagnostic tool in a FSM, but makes sense if you think about it.

PS, questions in the other thread is best, maybe mods will allow crossposting in this case......maybe.....

PPS...... think I asked before......where in North NJ are you? I have the tools.
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Old 11-14-2018, 08:01 PM   #12
Long Nguyen
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Default

Quote:
Originally Posted by BootsJunkie View Post
Just curious how many miles were on the motor? If very little, could explain no visible signs on the head/block/HG of leakage.





So if compression & leakdown's can't POSITIVELY identify a bad HG, and there won't necessarily be chocolate milk oil/coolant........ hell, even disassembling the motor to visually inspect HG's and mating surfaces can't even guarantee bad HG's....



Is there ANY 100% guaranteed test/sign/inspection that'll ID a bad HG?







This is going back to Charlie's "Nuts n Bolts" thread with the coolant pressure tester, I have one rented ATM and am going to perform the engine running test tonight *fingers crossed*


The engine has about 150miles. I had just finished the break in and it happened.





The gaskets show no signs of leaks.









Could you guys make out of something from these pictures?


I need to figure out whats really gone wrong before taking further actions.

One thing I forgot to mention. Please listen to this video clip. There are ticking noise and the radiator would shake pretty hard per tick noise.

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Old 11-29-2018, 12:53 AM   #13
PDXREALTOR
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OP - sorry to read about your issues. I hope you get them sorted. I don't have much to offer....but if you check the heads/block to make sure they aren't warped, put on new head gaskets and get it back in you could continue on and troubleshoot or discover the problem was solved. No?

I was led here from another thread where a guy was asking about capping off his water pump port that feeds the oil cooler. After reading the number of people state capping it was the worst idea, I'm surprised ets set you up with boots that split... Especially after 150 miles. I capped off my coolant line off the heater core to the crossover tube. I used jb weld and jammed a bolt in a fuel injection hose. That was a few thousand miles ago, now I'm worried.
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Old 11-29-2018, 02:58 PM   #14
Turpid Porpoise
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I would much rather see a block off plug replacing the banjo bolt than a rubber/silicone cap on the hard line.

It’s always been my opinion that if the heads come off, they get resurfaced. Period. The heads have been torqued, heat cycled and removed; they need resurfaced or checked by a competent machine shop at the very least.
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Old 11-29-2018, 11:32 PM   #15
Subie_
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hold on here guys... it's a bit late on the east coast and my vision might be a bit blurry atm, but am I seeing a... fire ring? as if that ej suddenly became a cummins diesel or something? Is there a recess in the head and/or block? Im a little confused.
Block and head flatness aside for a hot second, is there a reason OP isn't using an oem head gasket?

Edit: nope, not blurry vision. Just cant read apparently... does have darton sleves and fire rings lol
Have you talked to whoever did the machine work about the HG issue?

Last edited by Subie_; 11-29-2018 at 11:39 PM.
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Old 10-11-2023, 04:24 PM   #16
jaredbownds
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Did you ever identify the root cause?
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