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Head Gaskets

Hi Guys,

I have a 2002 Subaru Forester w/160,000 miles.

Recently I’ve been using about a quart of oil per tank of gas.

There are no visible leaks or puddles on the ground.

My mechanic seems to think it’s the head gaskets. Yikes! for $1500-

Is that my only option and if so is there any other quirks they can look for while they’ve got my car in pieces?

$1500 Is A Lot Of Money To “Invest” In An Old, High Miles Car, especially If Your “Mechanic Seems To Think” It’s The Head Gaskets.

Without knowing the maintenance / driving history of the vehicle, it’s difficult to tell what’s going on here. The engine could be worn out. You could put a lot more money in it and still have an old (8 1/2 - 9 1/2 years) high miles car when you’re done.

I think more diagnoses need to be done first.


Failing head gaskets are common with Subarus, but they usually result in the loss of coolant, not oil.

Besides, there are tests to confirm leaking head gaskets. No guessing is required.

I’d ask the have the PCV valve replaced and see if that makes any difference.

We usually ask for miles per quart of oil, but I’m assuming your gas tank will take you less than 500 miles, so you’re losing a LOT of oil.

Are you sure it’s not leaking anywhere?

Burning that much oil might indicate bad rings, which is even worse than bad head gaskets, but I’d look at the PCV valve first. And you may want to consult another mechanic for a second opinion before you agree to any major repairs.

I certainly was losing coolant. My mechanic put in a sealant to stop the leakage until he can work on it.
So the coolant leak has stopped. I burn oil when I’m doing highway miles. A tank for me is 320 miles or so.
checking at fill up my dip stick is near dry. Usually 1 quart brings it back up.
The temperature gauge never rises beyond normal.

A faulty PCV valve can cause increased oil consumption, but yours is really excessive. Burning this much oil is very bad for the catalytic converter, which is also expensive to replace.

Has anyone done a compression test?

How do you feel about keeping the car and fixing it vs trading it for something else?

The first step should be to perform a compression test on the engine and there is no way a mechanic should make a 1500 dollar guess at your expense.

Since there appears to be a lot murkiness even from mechanics about what constitutes good compression readings both a dry and wet test should be performed. The wet test verifies a problem with piston rings. Ideally, you’re looking for 180 PSI on all cylinders based on mileage, etc.
If there’s a 150 dry reading that shoots up to 190 on the wet test then there’s a ring problem no doubt about it.

It’s also possible to have a piston ring problem even with good by the numbers readings. Unfortunately, even a compression or leakdown test is not 100% definitive.

In truth my credit is shot so trading is out of the question.
If there are a few key points I can give my mechanic here to look out for I’d be grateful.

a rebuilt subie engine is 2000 ish… forget that 1500 fix. That truly IS A LOT of oil consumption you are talking about. PCV valve isnt a bad idea and very very overlooked…im certain you never replaced or cleaned it …no? If that valve goes bad it could force a lot of oil into places where it will be burned more easily…iffy but definitely something to check

Thanks_ I’m going to show all of this to the mechanic. Thanks

TRUE…Comp test doesnt verify the ability of the oil rings to seal…but is usually a good indicator of engine health…if you have good comp logic says you should have fine oil seal.

Maybe a can of rislone in the crancase to free up stuck oil rings? COuldnt hurt and is under 4 bucks.

But stuck rings are sort of a non issue these days…no? Back in the early days it was common… I guess its bec of better materials and fuels…