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2007 Subaru Forester - Oil Use

I have a 2007 Subaru Forester with a N/A 4 cyl and 5 speed manual tranny with just over 200,000 miles on it. For the past few months, it’s been using between 1 and 3 quarts of oil between oil changes. My mechanic and I can’t find any signs of a leak that big ( there’s a cam seal with a light sheen of dusty oil around it, and some dusty oil on the driver’s side head, just below the oil filler neck.

I put a UV dye in the oil, and the only spot that glowed under a black light was the bottom of the cam sensor, which doesn’t connect to any oil passages.

I noticed it uses more oil if I keep the RPMs high ( after a week of driving through the hills of Kentucky ).

I changed the PCV valve, which was very oily ( I shook it to see if it rattled and oil rained out of it ). But I lost a quart of oil in the week since I replaced that.

Does anyone have any ideas of what it could be, or where to look?

200,000 miles? I’m guessing your oil consumption is somewhere on the order of a quart every 1000 miles?

With no or inconsequential leaks I would say your engine is using the oil. You’ve replaced the PCV, I would check to make sure the breather hoses are free and clear, and other than that the wear is probably internal to the engine and no cause for concern.

Just check the oil regularly, top off when needed, and keep driving.

“I noticed it uses more oil if I keep the RPMs high ( after a week of driving through the hills of Kentucky )”

That might be normal . . . given the type of driving you mentioned and the fairly high mileage

“I changed the PCV valve, which was very oily ( I shook it to see if it rattled and oil rained out of it ).”

I’d say the piston rings are worn or tired, not sealing the way they did in their youth.

You could try a wet/dry compression test, but are you really thinking about putting money into a 10 year-old car with 200,000 miles? I’d use some for extra oil and save the rest for the inevitable replacement machine.

Why Not Try Something Like Lucas Oil Treatment (I think it comes in conventional and synthetic versions) In The Old Beast? It Will Probably Cut Consumption A Bit.

It is never a good idea to use your email address on a open website forum.
You can use the personal message part of this site and send @cdaquila a message and she can change it to what ever you want.

It’s got 200,000 miles, a new A/C compressor, new struts, new tires, new timing belt, gears and water pump and a new ( ish ) clutch. Other than using oil, there’s not much wrong with it. It still runs fine and idles at 750 RPM. I guess it will depend on price and timing for a rebuild, if it is the rings.

I’m debating using an oil treatment instead of the next quart. Or with, depending on what I get.

Volvo V70, you’re right. I guess I missed that with autofill. Thanks for pointing it out!

There’s no need to be thinking about a rebuild, there’s nothing wrong with that engine. So it uses a little oil. There’s no reason the engine won’t go for years more. Just check and drive on. A brand new car could use a quart of oil in a thousand miles.

I don’t know what the big deal is in having to add a quart of oil every thousand miles. Yes, I would prefer not to have to add any oil. However, a car with 200,000 miles that goes 1000 miles or more on a quart of oil is, in my opinion, doing quite well. My first car, a 1947 Pontiac, used a quart of oil every 250-300 miles. It got me where I needed to go and didn’t foul the spark plugs. I had a 1971 Ford Maverick. It used a quart of oil every 300 miles until I had the valve stem seals replaced and then the consumption dropped to a,quart every 1250 miles. To me, this was acceptable. The only reason I traded the Maverick was that I was doing a lot of traveling and with the “wheel barrow” ride of the Maverick, I was spending a fortune on Preparation-H and it wasn’t for the Maverick. Go purchase a case of oil of the correct viscosity of whatever oil is on sale at the discount store. With the money you save by not rebuilding your engine, buy a couple of quarts of good stuff for yourself to help you relax. There are a lot of posters on this board that are perfectionists and can’t stand an engine that takes any oil betwen changes. At 75 years of age, an engine that uses a little oil is no big deal to me. In fact, there may be a benefit to using oil. I have an old push lawnmower and the oil is always at the add oil mark after I have mowed the yard. I just fill it up and mow away. I don’t have any problems with mosquitoes – I kill them as I mow.

My 2006 Outback was also burning some oil, enough to clog the catalytic converter which has since been replaced. My mechanic recommended using BG EPR (Engine Performance Restoration) in the oil. Evidently the horizontal layout of the boxer engine design means that the rings are sitting in oil when the motor is off and they can get crud built up over time and miles. I’ve given it a couple of treatments and the oil burning now seems to be in the realm of a quart every 3,500 miles, quite an improvement. I left it in a bit longer than the instructions call for (about 50 miles of driving) and it seems to have made a difference. Your mileage may vary. Just a thought.

Check your owners manual and see if you can go up to a thicker grade of oil. It’s worked well for me in the past.

I’ve had very good results using this product to reduce oil consumption in engines.


Tester, I’ve used that before in other cars with decent results. I’m either going to use that or Lucas.

“A brand new car could use a quart of oil in a thousand miles.”

…or if it is a new Audi, it could need a quart every 600 miles, which is “normal”, according to the manufacturer…

jdmere: My ex wife is on her third Outback (1999, 2002, 2010). She loves them. I have driven all of them and understand why. It’s kind of sad that when one manufacturer extends the oil and filter changes all others due to marketing have to follow even if the design of their engines is different. I agree the boxer design (for the reasons you stated) should not go beyond 5,000 miles. I would also advise OP to not worry about a quart of oil every 1,000 miles. Check it weekly and add as necessary.

You could run a dry and wet compression test and see what happens. At 200k miles some ring/cylinder wear is to be expected along with the possibility of coked up oil wiper rings on the pistons.

Buy a new trunk accessory(case of oil) and top and drive on.

You can buy a case if you want, but at the rate you are losing it, just carry one quart in the trunk, store the rest in your shed. If you check the oil level frequently enough, you never need to add more than one quart at a time.

Have you pulled the plugs to see if one looks dirtier than the rest? This would help identify the offending cylinder or cylinders if only certain ones are burning oil.

I have had luck with the Gunk Engine Flush in the past. This stuff is solvents so you don’t drive with it. You pour it in the oil and let the engine idle a few minutes (directions on bottle) before you change the oil and filter (important).

I have also been known to suck some into the intake of neglected engines to help free sticky rings. Just be prepared for LOTS and LOTS of smoke when you start it back up!