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Discussion Starter #1
Hi There,
I have 57,000 miles on my 2010 Outback 4 cylinder. I was just making plans for the 60k service when the Check Engine light came on. The Cruise Control light, the Brake light and I guess the Stabilization light also came on. I took the car down to my dealer immediately. The check engine diagnostics showed that I had two clogged oil control valves.

I have been changing the oil and filter (Mobil 1, 5-30) at about 5k mile intervals since the car was new. I admit the last change was at about 7k miles.

The dealer told me I was not changing the oil frequently enough. I should be changing at about 3.5k even if I am using synthetics.

I checked with a second dealer and he told me the same thing, except that if I was using synthetic oil I could make the oil change interval 5k miles.

Really???? I have 2 german cars with oil change intervals at 15k (synthetic). Most of what I have read over the last few years says that you're wasting oil if you change at less than 5k miles.

I know Subaru's have a great reputation for reliability, but I'm a little disappointed to learn that I really have to stay on the oil changes or risk a catastrophic engine failure due to clogged oil control valves, which by the way are $400 to replace.

Any thoughts on this subject would be really appreciated. Thanks.
 

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Hi There,
I have 57,000 miles on my 2010 Outback 4 cylinder. I was just making plans for the 60k service when the Check Engine light came on. The Cruise Control light, the Brake light and I guess the Stabilization light also came on. I took the car down to my dealer immediately. The check engine diagnostics showed that I had two clogged oil control valves.

I have been changing the oil and filter (Mobil 1, 5-30) at about 5k mile intervals since the car was new. I admit the last change was at about 7k miles.

The dealer told me I was not changing the oil frequently enough. I should be changing at about 3.5k even if I am using synthetics.

I checked with a second dealer and he told me the same thing, except that if I was using synthetic oil I could make the oil change interval 5k miles.

Really???? I have 2 german cars with oil change intervals at 15k (synthetic). Most of what I have read over the last few years says that you're wasting oil if you change at less than 5k miles.

I know Subaru's have a great reputation for reliability, but I'm a little disappointed to learn that I really have to stay on the oil changes or risk a catastrophic engine failure due to clogged oil control valves, which by the way are $400 to replace.

Any thoughts on this subject would be really appreciated. Thanks.
Your driving conditions determine when the oil needs to be changed. I've never seen this issue have just shy of 50K and run 10-30 mobile or Cheveron pending which has the best deal going at the time. Zero issues but my driving conditions are pretty mild California semi rural type driving. I generally change the oil between 5000 -7000 miles depending on the vehicle use during that period- hauling the trailer or road trips I generally shoot for the 5000 mile range. Clogged oil systems would suggest either different oil is needed or changing the oil sooner.

Where exactly are you driving the car and what type of use?
 

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2012 Outback 2.5i CVT
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If you are changing every 5,000 miles with synthetic I don't see how that isn't frequent enough. Isn't that the frequency identified in the car's manual for more severe driving conditions?
 

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Discussion Starter #4
Thanks for your reply! N. California, semi rural same as you. I'm not pulling a trailer and I'm using tier 1 gas, if that matters. I changed the oil 3.5k miles ago. If I was careless and under filled with fresh oil, it would cause the oil pressure to be low and that would cause the oil control valves not to work and trigger the error codes. Dealer said the valves were clogged so I don't think low oil pressure was the problem. I always use Mobil 1 and I change oil and filter at the same time mostly at about 5k. Still a mystery to me what is going on. Thanks again.
 

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If you are changing every 5,000 miles with synthetic I don't see how that isn't frequent enough. Isn't that the frequency identified in the car's manual for more severe driving conditions?
Could be something up with the oil. I would try a different brand see how that goes.
 

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Discussion Starter #6
I've had two dealers, San Jose, CA and Santa Cruz, CA, tell me that 5k intervals is the maximum to avoid this problem.
 

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Thanks for your reply! N. California, semi rural same as you. I'm not pulling a trailer and I'm using tier 1 gas, if that matters. I changed the oil 3.5k miles ago. If I was careless and under filled with fresh oil, it would cause the oil pressure to be low and that would cause the oil control valves not to work and trigger the error codes. Dealer said the valves were clogged so I don't think low oil pressure was the problem. I always use Mobil 1 and I change oil and filter at the same time mostly at about 5k. Still a mystery to me what is going on. Thanks again.
Yes you need to be pretty cautious on the refill- I generally let the car sit a little while after putting 4quarts in. Then find that a little bit of a top off is needed when I check again.

For the older 2.5 which is in the cars up through 2012 I'm a little gun shy of running the 5W oils given my prior 2.5 from the same design ran 180K hard abused miles with zero issues running 10-30 mainly Mobil 1 but I wasn't religiously attached to that brand. I also like the Cheveron oils.

I run the cheap off brand little gas station gas - never had any fuel related issues.
 

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What the hey is an oil-control valve?
It provides oil to the part that adjusts cam shaft phase. I believe the pressure it provides, as determined by the ECM, adjusts the cam shaft because these are variable cam engines. I'm not 100% up on how this system works in detail but that's the short of it.
 

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Ah, similar to something that gave my friend some grief on his high-mileage vtech engine.

Computer said the vtech system was not engaging (based on the oil pressure switch not responding), engine would not rev up.

The shop couldn't figure out if the system really wasn't working, if the passages were choked, the pressure switch was bad, the solenoid was malfunctioning, etc.

He always used synthetic so I figured no passages were gunked up.

I said it was a high mileage engine, probably oil pressure is low, try 10-40.
Worked like a charm.
 

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2001 VDC/SC One of a Kind
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At that low of mileage and the interval you state, unless the oil is overheating, I doubt they are clogged. If they are, there are two ways to remedy the issue.

One is drain the oil out of the engine and pour in a gallon of Gunk engine flush and run it at idle for about 5 minutes then drive it for a few more in a manner that would activate the solenoids to work the valves. I'd say probably speed up to 50, coast down, speed back up and do this 5 or 6 times. Then drain it, change the filter and oil and drive it like normal. Clear the ECM and see if it comes back.

The other is remove the valves. If there is carbon build up, clean it and reinstall. If there isn't, the dealer service got it wrong.

Low oil level will not necessarily cause low oil pressure. It will cause low flow which will not allow the cam actuator to work, which will throw a code. Same with the VTEC solenoids on the Hondas. I very rarely replaced a VTEC solenoid. An issue with the cam advance was low oil or a seal leak on the solenoid. And never a clogged valve. GM and Nissan, different story. Run it low on oil a couple times and the valves are frozen shut or open.

If you are following information in the owner's manual and have been using Mobil 1 Synthetic oil there are two ways to beat the dealer cost if the valve is indeed clogged. One is Subaru's maintenance schedule. The other is contact Mobil Oil. The only time I have seen Mobil synthetic sludge and create heavy carbon build up is when its been run low and for a long time allowing it to overheat.

I've attached a breakdown of the solenoid/valve. Its not difficult to remove whether you clean it or replace it.

.
 

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Discussion Starter #12
Thank you for taking the time to provide such an informed response! The dealer offered to flush the valves if I didn't want to spend $400 replacing them. I opted for the flush. They also told me the flush process never solves the problem for very long. I am skeptical. I'm going to keep my oil change schedule at 5k (with synthetic), make doubly sure my oil level does not drop below 1/2 quart low, just to make sure low oil pressure is not the culprit. If I need to replace the valves, I will take your advice and do it myself. The one in front is easy to access, the one in the rear is pretty easy to find also. I do like the car an awful lot. Although I notice the 2013 has the oil filter relocated to a more convenient location and the oil is now spec'd at synthetic 0-20.
Thank you again.
 

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A slightly different view . .

Assuming that this is related to the variable valve lift (VVL) function, when the CEL was set, there would have been one or more diagnostic trouble codes registered. The codes are important to the diagnosis. Do you know what they are?

The VVL system has been in use in the 2.5 boxer since 2006, and I understand is borrowed from a similar Honda system that has been around even longer. I can't recall any instances of the oil control valves (actually they are solenoid valves) becoming clogged. However, there are threads here relating to failures of the pressure sensor, the solenoid, and in one case I recall, a missing gasket. There was also one or two reports of codes being set which were traced, as unusual as it seems, to the use of an aftermarket filter. I would guess this is probably more along the lines of cardoc's explanation of low pressure effects.

It just seems rather unlikely both valves (there's on one each head) would become clogged at much the same time.

How did the dealer come to that conclusion (what troubleshooting was done?), and did the other dealers do independent troubleshooting, or were they commenting on the oil change interval question only on the basis of the first dealer's report?
 
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