Head gasket failures on unmodified engines?
 

The latest iteration of the BRZ has me considering getting back into an 86, but...

My wife's 2009 Impreza recently needed to have its head gasket (or is that plural?) replaced. It has, maybe, 80K miles on it. Looking around other Subaru forums and talking with local mechanics, this appears to be a known Subaru problem.

My question: do the 86s also have this issue?

I have read a couple of hundred thousand posts and do not recall ever seeing one single blown head gasket on a stock engine. Different head and block than the ones you have read about.

Two different motors. I believe it's an ej motor in your wife's impreza while the BRZ has an fa motor. Haven't seen any head gasket issues on these cars.

The head gasket issue is not on all ej motors either. They are more common on certain ones then others.

I personally know a guy whose engine head gasket blew, BUT he was an avid track enthusiast with many track miles, definitely it is not an issue on this FA20 motors.

I am not sure there's large enough of a sample size of cars over 80k miles to answer your question definitively. That said, 80k miles is simply too little miles for the average engine of any kind to experience a head gasket failure.

And yes, in the case of Subaru engines you need head gaskets.

I've yet to see a definitive case of a blown head gasket on a non-modified 86 with 80K miles. I've seen plenty of modified 86's driven hard without a blown head gasket.. with 70K miles or more (mine's included).

When Subaru switched to the chain driven engine('11 in Forester, maybe '12 in Impreza/Crosstrek) the external head gasket leaks seemed to have stopped. They now leak from other places(randomly, not from abuse or mods) due to using silicone sealer instead of gaskets. Buy one, oil leaks are covered for 60k(Subaru at least, not sure on Toyota warranty).


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There was one where a guy bought a stock BRZ used with 3000 miles on it and discovered it had a blown head gasket. Of course, there's no telling what was done to it during that 3000 miles before he got it, but the dealership fixed it under warranty.

Did your wife's car ever have the coolant replaced? Subaru engines require the Cooling System Conditioner part number SOA635071. Without it, the head gaskets may leak. Just wondering...

I don't know. She pretty much tends to the care and feeding of her car. Do you know when the treatment is required?

Since we are focusing on tiny sample sets, I should point out that my friend's wife's 1999 Impreza RS 2.5 (original owner) has never had engine problems of any kind.

It was also regularly maintained.

Anytime the coolant is drained out of the car, Subaru recommends adding their cooling system conditioner when refilling with antifreeze. They put it in there from the factory so unless you have changed your coolant, it should still be in there.

Does this also apply to the BRZ/FR-S? Link to the product?

The factory service manual says nothing about using the conditioner to prevent head gasket leaks.

If this was a known issue they would list it as "required materials" instead of "recommended materials" in the Service Manual.

You're right. It's not required but recommended. The service manual gives the part number for the coolant and the cooling system conditioner so obviously it can be used in a BRZ.


I guess if you want to leave it out, that's your choice. But it's only $6 or so, so why leave it out and take that chance?

Yes it's only $6, but I've never heard of a modern engine requiring a specific type of coolant conditioner to prevent a head gasket leak.

-alex

Here's some additional info on SOA635071.

Looks like it was intended for earlier engines with head gasket problems. I am very doubtful we would need it in a modern engine.

Look at the bottle design vs the normal Holts Radweld.

http://www.scoobyenthusiast.com/suba...ner-soa635071/

What point do you think you're making?

There's simply not enough high-mileage FRS/86/BRZ documented among enthusiast circles to say "this engine has a similar head gasket problem like older Subaru engines".

Maybe a few years down the road, there will be some "a-ha" moment when some flaw in the FA20 is discovered from a longevity perspective. But there simply isn't enough high mileage cars to say whether the head gasket will just blow up after 100k or not.

The side discussion about coolant conditioners is more about previous engine design flaws and preventive maintenance when you change coolant.

Nissan had a "flaw" on the KA24DE for many years, where the upper timing chain guide will rattle and break off. For years, Nissan told techs to replace the tensioner and guides as a fix, since it tends to rattle because the chain is losing tension as the oil pump ages.

Then about 10 years after the KA24DE was introduced, Nissan updated their TSB to simply tell technicians to remove the guide and not bother with replacing it.

So to answer your question: no there is no known head gasket issue on this engine. Your wife's car's issue is irrelevant and unrelated and should not influence your buying decision.

-alex

Thank you for the longer explanation. Your previous post was unclear to me. :-)

My 2017 did it at 6k. I was driving down the freeway and when I got off flames poured out from under the hood. The gasket leak caused the coolant reservoir to overflow with oil, the coolant overflow hole squirts the excess out below the engine and above the exhaust where it ignited. No engine mods and I did the break in period properly so I have no idea what could have caused it.https://uploads.tapatalk-cdn.com/201...66c22dfddf.jpghttps://uploads.tapatalk-cdn.com/201...a876b482bf.jpg

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Why does it look like you're fixing that yourself on a 6k engine? Problems with a warranty claim?

HPDE Time Attack enthusiast chiming in here with what I have seen with tracked FA20s.

I have just blown my 2nd head gasket. Both gasket blew under boost. 8 psi and 12-13 psi respectively. Both engines had about 40-50 track days on them.

Two other track buddies blew the gaskets under boost at about the same # of track days.

One track buddy blew his gasket while NA (header + tune + e85) but his motor had 60+ track days on it.

All of these drivers were driving at a rate of ~20 track days per year.

First symptoms observed by all drivers was coolant overflow bottle was overflowing with coolant during hot laps. Combustion pressure pushing coolant out of the system. Black specs of gasket coating could be observed in coolant. At idle with radiator cap open bubbles could be seen periodically rising to the radiator cap neck.

https://scontent-sjc3-1.xx.fbcdn.net...75&oe=5E99BF81

Here is a slightly larger sample size:

Mechanic here, I'm under all makes of cars pretty often. Before buying my '17 I paid attention when I was under a subaru. Since the F engines have been put in service, amongst all our fleet of customers, I've not seen a single one leaking oil from the head gaskets like the EJs did. That old guy with a 16000km XV? He just got a new transmission under warranty, but the engine is fine. That salesman with 215000km on his outback? He's on his 3rd exhaust manifold and we did the rear diff seals this fall, but the engine is dry as a bone.

Those are the two extremes, but everything in between is the same, it's not a problematic engine like the EJ25 was. It's not a perfect engine, it's <<<sensitive>>> to RTV abuse for example, but for me there's no fear that I'll wake up one morning with it pissing oil from the head gaskets like an EJ.

Does anyone have recommendations for making head gaskets last longer? Is OEM or a particular aftermarket HG better? I blew a stock one and more than likely now a Cometic one.

2013 BRZ... 23000 miles. Headgasket started spraying oil top of the motor under the intake manifold. Used about a quart of oil month. I could place a paper towel on the HG seam leaving my house and when I arrived at the office <5 miles later, SOAKED with oil. The oil would leak onto the headers and fill my cabin with smoke.

Car was under CPO "Gold" level warranty. The Subie dealer techs refused to confirm it was leaking, even after 3 visits and 3 weeks worth of stays.

No, I don't think all the FA motors leak, but for us when it does, it sucks.
I ended up selling the car back to the dealer I got it from.