Subaru burning 5 quarts every three days

I have a Subaru STI 2012 and it’s burning 5 quarts of oil every three days. Any ideas of what’s could be causing it? It’s only got 40k miles so I wouldn’t think it would be the pistion rings. It’s getting kinda expensive to drive around since it’s basically a two stroke now.

Hard to believe it is running if burning that much oil.

It only runs rough for the first 5 minutes after a cold start, then when I’m driving 55mph or faster. It also starts hard as you might imagine.

At this rate you are going to ruin your catalytic converter or both if you have 2. That will be expensive on top of the engine overhaul . As for cause it could be several things but all that matters is fixing this problem. A rebuild , a used engine or even a crate engine new. Your choice.

Call your local Subaru dealer, and see if your vehicle is covered under this warrant.


I’ve never taken it to the dealer since I bought it and I’ve put a stage three clutch and flywheel in her with a custom tune, and done all the work and oil changes myself. I did actually give them a call about it but they said I voided my warranty by working on it myself.

Only if they can prove that your mods caused the failure.

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If it’s truly burning 5 quarts every 3 days (!), and you don’t know why yourself… you need a professional. My goodness.

I would suspect that the turbo has a leak.

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How often do you change the motor oil; both as to miles and time.

First step is to run a dry and wet compression test. If the test shows a piston ring problem then odds are you weren’t changing the oil often enough.

Over the years I’ve seen probably a dozen Subaru engines with fewer miles than yours that were damaged goods and the common thread was lack of oil changes.

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I don’t believe you are burning that much oil in the engine. Try changing the PCV valve to see if that makes some change. Also check to see if the engine oil is leaking into the transmission fluid.

I’ve been pretty religious when it comes to the oil changes though. Every 6-7000 miles I’ve changed it, using a fram filter and super tech oil of course but oil is oil, right? I don’t think that would be the cause. @Cougar I wasn’t able to find the pcv valve on my engine, maybe it doesn’t have one? I’m planning on taking it to Subaru in to the dealership this morning to at least see what they find with an hour of diagnostic time and maybe see if it is actually under warranty like @Tester suggested.

How long does it take you to accumulate 6k-7k miles?
If it is longer than 6 months, then you aren’t changing the oil often enough.

Not exactly. The only requirement is that IF warranty is denied, the reason must be stated. This shifts the burden of proof onto the owner to prove that the mods DID NOT cause the failure.

Where this plays out is in arbitration or in court where the owner has to present expert testimony. Needless to say, the car manufacturer has plenty of experts to chose from.

That’s not the only requirement. Other requirements include the reason must be legitimate. If you put a K&N air filter on the car and they try to say that’s why your radio went out, that’s not going to fly because there’s no way an air filter killed the radio.

In this case, if OP can show that a significant percentage of vehicles of his year/engine have the same problem he does, then it’s not reasonable to conclude that his vehicle would have been the rare exception to the problem if only he had not put mods on the car.

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So I just got a call back from the dealer, they said the technician found the pcv valve was plugged with sluge and he pulled the both valve covers and found a large amount of sludge on the valve train, which I find hard to believe because I was consitant with the oil changes. They said it can’t be covered under warranty because it had never been brought in for an oil change at one of the Subaru dealerships, so there’s never been an oil change as far as their records go, and if I was changing the oil in it myself they said I may have not put the correct oil in it and there’s no proof I did if often enough SMH. They also said he thinks the valve stem seals are leaking. So he said I have two choices, a new/rebuilt long block, or they take the heads off and send them to the machine shop and do an engine flush to try and get rid of the sludge along with a new pcv valve. They also wanna put to cats in it because of how much oil it was burning. @VDCdriver as far as how often I change it, I only drive it in the summer and do one oil change in the spring because I don’t often drive more then 6000 miles in it during the summer, I put it in the garage in the winter.

This is where you show them the receipts you saved to prove you bought oil and filters and the type was correct as indicated on the receipt. When you do oil changes on your own during the warranty period, the onus is on you to save those receipts as evidence. That being said, one change a year will void the warranty due to the elapsed time element being exceeded.

Sounds like lots of short trips, stops and starts. That’s the most severe service conditions and warrants more frequent oil changes even though the mileage is low.

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The maintenance schedule indicates to change the oil every 3,750 miles with synthetic oil, were you using synthetic oil? SuperTech is cheap oil, I wouldn’t trust it for annual oil changes. If I were to exceed the oil change recommendation listed by the manufacture I would use Mobil 1.


@TwinTurbo I have the receipts somewhere, I’ll see what they say when I show them. But I only drove it for the 6-7 months then it’s in winter storage.

@Nevada_545 Yikes is it really? The super tech is partially synthetic I think.

So what should I do, I still have a loan on the car… Should I put in a long block or try the engine flush with machined heads and a valve job? Or do you guys think it’s not worth putting the money in?