It is always difficult to assess a problem using the internet and although it is unlikely, the head gaskets could have failed on your friends Subaru.

What I can tell you is that your friend needs to take the vehicle to a different mechanic as It is NOT common for a 2017 Subaru to have head gasket problems.

It is true that Subarus had head gasket problems up to the 2009 models but after this time, the head gaskets were changed to Multi Layer Steel which has all but eliminated the problem.

Seagrass

 

Yep. I call BS.

The only way a HG blows on a post 2010 H4 is if it is run hot for a while. On a 17 that means the temp went to the top and stayed there.

 

Can’t say you’ll see a plethora of HG failure posts on this forum mainly due to it not being a normal issue with the FB25

The mechanic may simply be referring to the old NA EJ motors from the early days having head gasket issues. Tough to shake a reputation no matter how long it’s been fixed I guess

 

That was really all I was trying to do, which is prove to him that it isn't a current problem.He eventually brought it to Subaru and reached out to corporate. If it's an internal issue they'll cover it.That's how I understand it.

 

You didn't say, does your friend have a 2.5 or 3.6?

When my car was in for the transmission pump leak TSB, they told me my 3.6R had seeping head gaskets and quoted me $4500, if I chose to fix it. I was very consistent with keeping my coolant fresh, to try and avoid HG problems, and my car never overheated. It had 145k miles at this point. I told the dealership to pound sand and sold the car (not for that reason).


A few weeks later, a guy on the Outback FB group had the exact same diagnosis and he only had 56k miles. I reached out to him and he used the same dealer I did.

With all that said, it's very possible that your friend has a HG leaking.

 

You didn't say, does your friend have a 2.5 or 3.6?

When my car was in for the transmission pump leak TSB, they told me my 3.6R had seeping head gaskets and quoted me $4500, if I chose to fix it. I was very consistent with keeping my coolant fresh, to try and avoid HG problems, and my car never overheated. It had 145k miles at this point. I told the dealership to pound sand and sold the car (not for that reason).


A few weeks later, a guy on the Outback FB group had the exact same diagnosis and he only had 56k miles. I reached out to him and he used the same dealer I did.

With all that said, it's very possible that your friend has a HG leaking.

Well it is a2.5l . Oh I didn't say it wasn't possible ,my point was that it is rare that a Gen 5 has the problem.

 

I just purchased a 2017 with 68k miles. Head gasket is leaking. They tested and found combustion gases in the coolant system.

 

Read the posts above and get a second opinion.

When a Subaru head gasket fails there is rarely combustion gasses in the coolant.

Not saying the head gasket has not failed just saying get a second opinion before you spend lots of money on an uncommon problem.

Seagrass

 

So I am having coolant loss. They pressure tested the system and it passed. But they found the combustion gas in the coolant. What other issues would cause the car to fail the combustion leak test?

 

How much coolant loss?

The cooling system is open to the atmosphere and some coolant loss is expected.

Other forum members advise they add coolant periodically maybe a cup full every six months or so.

Seagrass

 

 

It was about half a gallon low and overheated pulling off the highway when there wasn’t enough RPM and airflow. Pulled over and turned heat on, was blowing cold.

 

Sounds like you have a slow coolant leak that needs to be monitored (not necessarily a head gasket leak).

You need to check the coolant level in the overflow AND radiator when the engine is cool and top up as required. Check every day until you know the radiator is staying topped up.

The cooling system only holds 6 quarts of coolant and even half a quart low will cause overheating.

Your problem may be a faulty radiator cap (only use a genuine Subaru cap) that is allowing coolant out into the overflow but not allowing coolant to be drawn back into the radiator.

Let us know what you find as it may help others.

Seagrass

 

Purchased a Head Gasket Combustion Leak Test Kit and the test showed combustion gas in the coolant system. Replaced a leaking PCV Valve, PCV union and hoses, Radiator and cap, coolant, crossover pipe o-rings, and intake gaskets. Used coolant funnel kit to remove all air.

Coolant reservoir is filling up after driving and the car is still failing the Head Gasket Combustion Leak Test.

Seems like it is the head gasket after all, despite no external signs of leaking.