Oil Light turns on, but oil level is fine?

I have an older Subaru Outback. I know the head gaskets are failing but the repair would cost more than the car is worth so I plan to just drive it until it dies and then scrap it and move on.

The "service engine soon" light comes on a lot, the code is related to an oxygen sensor in the exhaust, but the root cause of the issue is the fact that the car burns oil or coolant or whatever.

Lately the oil light has been coming on for brief periods of time. It comes on when you first start the car and all the dash lights turn on, but when the other lights turn off the oil light will stay on a few seconds longer, sometimes for 30-60 seconds. then it turns off.

I've checked the oil many times and the oil level is good. Its been less than 2,000 miles since my last oil change and the oil doesn't look black or burned, so its not due to be changed.

I'm just wondering what could be causing the oil light? Is it possible for the leaking gaskets to allow coolant into the oil? Like maybe its burning or leaking oil but the level looks right because coolant seeps in? Could there be a problem with the oil filter, like maybe its clogged or something? The coolant does run low over time, I top it off every few months but its not bad.

I'm planning to take the car on a (somewhat) long trip - about 300 miles round trip next weekend so if there's something simple & cheap I can do before then like replacing the filter I'm all ears.

Thanks.

Erik2018-09-21T23:35:59Z

Could be a bad oil level sensor.

Dan B2018-09-12T04:05:48Z

Could be a faulty oil pressure sensor switch causing the oil light to come on. About $15 for a new one.

thebax20062018-09-11T11:23:31Z

If the oil level is near or at the top mark on the dipstick replace the oil pressure warning light sending unit. They cost under $30. Do a search on youtube for how to replace it. They are a common problem.
if the light still comes on have a mechanic check the oil pressure.

Rolomatic2018-09-11T05:18:32Z

Sounds like your oil sump pick up screen is plugged up, that motor is running on borrowed time my friend.

*Worn bearings / oil pump are the opposite, good oil pressure until the oil gets hot. You have a restriction
or see the video below on how to diagnose a broken / cracked oil pickup screen and tube assembly issue.

*I did a bit of research for you, it seems the 2 liter steel pickup tube stress cracks over time because the aluminum boxer block expands more under heat then the steel tube causing it to defect crack over time. If this is the case, simply pulling the oil pan and fixing the broken oil pickup assembly will fix your problems.

*The dealer is quite aware of this time stress cracking defect and they are hoping you will trade it in cheap before engine damage occurs so they can do a simple fix and sell it again for top resale $. I would never go back to that Subaru dealer again for service! Dealers are very dishonest in most cases, they are only good for warranty work. They are profit based, if they can get your old car at half BB value and know the simple fix, they will work you over on the sales grill pyre. This is why you do some research before going to the dealer service rep.

https://www.youtube.com/watch?v=7OokXhL-A5c

Joe2018-09-10T16:59:00Z

If you don t change the oil filter when you change the oil, the filter could well be clogged, or the check valve stuck.

But, honestly... I think that there s something more seriously wrong with your engine.

Look under the oil filler cap: If there s a creamy substance that looks like chocolate milkshake, coolant is getting into the oil.
Look at the coolant recovery tank: If oil is getting into the coolant, you ll see oil stains through the plastic.

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