H6 Head gasket replacement

[SteveB]

Today I decided to proceed with changing the head gaskets on my newly aquired 2003 Outback LL Bean H6 engine. I have the manual that someone here posted (thank you Very much). I will pull the engine this week and begin the replacement procedure right away. If you have any experience with the H6 I would appreciate any tips. I expect that I will need some specialty tools as stated in the procedure so that may be the biggest challenge. The other is to decide whose head gaskets to buy. I saw on the forum that Subaru OEM from the dealer is recommended so any input to a better source for these gaskets would be appreciated. More top follow and thanks for any advice you may have.

[AWDFTW]

Why are you changing the HGs? Have they had an issue? The H6 engine is almost totally HG failure free, think I have heard of 3 failures ever.

[SteveB]

The bubbles in the coolant, overheating due to pockets of air in the system soon after I bleed it. The coolant system has no leaks I can find and I just replaced the radiator. ( O'Reilly had the radiator for the H6 for $150.00)

[driveby]

Have you done a block test to confirm that the bubbles are exhaust gas?

It would suck to pull the engine & heads...and then find out that the problem was something minor like your radiator cap.

-Jeff

[bigdadi]

overheat may be due to something else, install non-OEM thermostat, bubble not burped out completely, or bad radiator cap.

You can buy a kid ($50) to test whether combustion gas in coolant, that is the proof of internal head gasket problem. Due to cross-contaminated, do you smell of coolant from the exhaust?
Head Gasket or Combustion Leak Test Procedure (Gasoline Engines Only)

[SteveB]

I just replaced the radiator and the radiator cap. The oil is diluted with antifreeze and I have a continuous bubbling coming out of the radiator after burping the system. On a 10 mile drive (no longer possible as I won't start the engine with the diluted oil symptom) the car uses antifreeze. Seems to be a head, or head gasket issue. The plan is to pull the engine and heads this weekend and order a complete engine gasket set from the OEM Subaru online dealer to fix the problem. I would love for it to not be a head gasket but I don't see what else could cause all of these symptoms.fficeffice" />>>

Steve

Originally Posted by bigdadi

overheat may be due to something else, install non-OEM thermostat, bubble not burped out completely, or bad radiator cap.

You can buy a kid ($50) to test whether combustion gas in coolant, that is the proof of internal head gasket problem. Due to cross-contaminated, do you smell of coolant from the exhaust?
Head Gasket or Combustion Leak Test Procedure (Gasoline Engines Only)

[CNY_Dave]

Yeah, all the other answers are ugly, unless it's the oil cooler.

Not sure if that would cause bubbles in the coolant, but who knows.

If it cracked/rusted internally that would create an oil/coolant exchange point.


Dave

[woestracer]

You will also get the cylinderheads checked for flatness and have them milled if required? Good moment to have a good look at all other parts there like valve seals etc.

[SteveB]

I will indeed. I plan to stop off at my machine shop on the way home to get him lined up. I will buy the complete engine gasket kit so valve stem seals will be no issue. Good point though.

Originally Posted by woestracer

You will also get the cylinderheads checked for flatness and have them milled if required? Good moment to have a good look at all other parts there like valve seals etc.

[SteveB]

The engine came out on Saturday, about a 8 hour process. I have the intake manifold off as well as the timing chain cover and will remove the timing chain assy as well as rear cover, cams oil and water pump and then remove the heads. Gasket kit is on order $270.00 for a complete engine gasket set. The Liberty manual I downloaded from someone on this site is really good. It is making this job much less intimidating than it could be.