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[Solved] Desperately Trying to Find What's Wrong with my Engine


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Car: 2016 Subaru Legacy Premium

Long Story Short: I changed oil myself, was stupid only put 1/5th of what it needed, proceeded to drive it for 20 minutes, car dies. Pulled over, find out it needs oil so I fill it. Has trouble starting up but it runs enough to get me home (5-10 minutes). Starts up fine in the morning, so I drive it, dies after 5 minutes on the road. Tow to a repair shop, they say Engine's burning oil way too fast, after a "thorough inspection" ($$) they don't know specifics nor what to fix so they say "We have a used engine 50,000 miles for 6,200."

Side Notes:

Fresh Battery, replaced myself 5 weeks prior but MIGHT'VE blown a fuse or two

Had/has enough gasoline

Used the correct oil and filter

No leaks were found

The mechanics only could tell me that the engine was burning oil too fast. I asked for clarification and they couldn't give me any!


Any help would be greatly appreciated, I'm looking at nearly $7,000 at the dealership for a new engine including labor and other necessary parts 🙁

Thank you for your time!

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5 Answers

Your piston rings are definitely toast if it's burning oil way too fast and dying. A compression test would confirm this, but that's about all you'll get that's useful out of doing one. The fact it dies is a pretty good indicator the compression is bad.


I'm surprised you didn't notice a bunch of weird noise as soon as the car started. My step dad used to be really OCD about getting as much of the old oil out of his motors as possible -let it drip for 30 minutes or so, then put it back together. One change he apparently got too much out, and the motor made all kinds of metal on metal noise for about 5 seconds before the oil made it back through the engine. I always check the dipstick before I start the engine after an oil change.


Driving for 20 minutes with 1/5th of the required oil quantity = goodbye engine.

Didn’t you have any warning lights turn on while you were driving, saying the oil pressure is too low? Or the engine overheating? Or CEL illuminating? Any burning smell?

It’s time for a new engine/car, I’m afraid. 

Out of curiosity, did you tell the repair shop about the snafu

Yes I explained everything, every single snafu :/
There was a single warning light that I didn't notice until 30 seconds before it died-
YES it did give off a strange smell when it first died-
Aw sh*t I had a feeling it would come down to that... while I have you, would you happen to know a website/store I can find an affordable yet reliable used engine?

Buggah! As the others have mentioned, very bad things happen when an engine is starved of oil. Regarding the replacement engine, I recommend you either stick with your mechanic’s sources or go brand new via the dealer route as you don’t want to buy the cheapest engine online, you can find and then having no guarantee if things go pear shaped, in future. Also, seriously consider selling this car as-is (if the option exists) and use this opportunity to buy another vehicle, that still has its original engine & transmission. Good luck.


I agree engine is probably damaged 1/5 th the oil so 1 quart in a 5 quart system? you could do a compression and leak down test to confirm   

How likely would you say the test could result in finding something repairable?

Not likely. Also, compression or leakdown test won't show bearing damage which is very likely in this scenario.


Really the best option to save the car if it is otherwise in good condition is a good used low-mileage engine, either from a local wreck or one of those that gets imported from Japan.

Aw man I understand - would you recommend a good site or shop for the Japanese-imported engines or local wrecks? I'm having trouble finding solid reviews on some of the ones I found on google


There are ways to test and view engines, from wet and dry compression tests to a visual examination of cylinders with a boroscope.

If your engine is aluminum, as most are, well, that's a soft metal easily damaged by heat and friction. 20 minutes is enough to damage it.

And, given that the Subaru Legacy has a horizontal layout of pistons (Boxer Engine), there's a tendency for poor maintenance, intended or otherwise, to result in a blown head gasket.

Given the information we have, Chuck is right. A good used low-mile engine, with a warranty, imported, may be the best choice, presuming that the ECM can be programmed to accept it.


Scotty's answer at 8:35