Diagnosis help - potential engine failure?

[Koniko]

Having a major issue with my Legacy that I'm trying to diagnose, folks on the local Subaru forum I've been on for years pointed me to LegacyGT in hopes of getting some input/advice. Here's what I'm looking at:

2015 Legacy Limited 2.5 CVT, around 152k mi

About a week ago, my wife was leaving a store parking lot when she states it suddenly started "chugging." She couldn't hear the engine well due to background noise so I don't know if there was a misfire but she could at least tell the engine was struggling. After a few seconds the engine then shut off and wouldn't restart. She tried hitting the ignition button a few times but although the starter seemed to engage it wouldn't turn over and then the starter began to smoke.

Got it towed home, couldn't really tell what was wrong so I replaced the battery and starter to rule them out (needed both at this point anyway). Tried the ignition, again could hear that the starter engaged but the engine didn't turn over. At this point I finally thought to try turning the crank by hand and it wouldn't budge. Turned counter-clockwise and it felt fine for nearly a full rotation (few degrees shy of 360°) before hitting an obstruction. Turned clockwise again, same thing. Rotates freely and feels/sounds normal but stops hard at the same point.

Fluids are all full and oil has no metal in it (on the dipstick anyway), pulled a cam position sensor and confirmed at least one gear is still turning with the crank. My wife states the only other symptom she's noticed lately is that when accelerating from a stop it seems to take more effort to get the car moving. That in itself seems to me like potentially a torque converter issue but I'm not sure if it correlates.

Hate to make this my first post here but I would greatly appreciate any input as to what may be causing this, if anyone's experienced the same or has a suggestion. Thanks!

[silverton]

Your wife should have brought this to your attention far far sooner.  Though it can be difficult to push through some of the compression strokes, a hard stop is not good, and to the point it cooked the starter? yeesh!

excessive wear metals may not be present to the human eye on the dipstick, if you want to be sure send a sample to blackstone.  I haven't experienced a torque converter failing in this way, but i suppose it could happen!

[Koniko]

1 minute ago, silverton said:

Your wife should have brought this to your attention far far sooner.  Though it can be difficult to push through some of the compression strokes, a hard stop is not good, and to the point it cooked the starter? yeesh!

excessive wear metals may not be present to the human eye on the dipstick, if you want to be sure send a sample to blackstone.  I haven't experienced a torque converter failing in this way, but i suppose it could happen!

It was a pretty sudden failure with the engine stalling out seconds after it began running poorly, and all she did afterward was try to start it back up as she was blocking traffic so I can't really fault her for that. It has a push-button ignition and when she hit it the car just kept trying to turn the engine over until the starter burned out. 

[silverton]

can you get a full 360 out of the crank? or almost?  If so you might be able to get at the four bolts that hold the torque converter to the flex plate. this would allow the engine to spin freely of the transmission. unbolting the throttle body makes this much easier.

[Koniko]

I can get the engine to rotate nearly 360°, not quite all the way. BUT there's another concern I'm not sure how I didn't notice earlier. The oil looks to be overfilled quite a bit. Level on the dipstick is about an inch over the max mark. My wife has occasionally had to top it off due to normal (for Subaru) consumption and I'm guessing she just added some without checking the level first at least once or twice.

[Koniko]

1 hour ago, Koniko said:

I can get the engine to rotate nearly 360°, not quite all the way. BUT there's another concern I'm not sure how I didn't notice earlier. The oil looks to be overfilled quite a bit. Level on the dipstick is about an inch over the max mark. My wife has occasionally had to top it off due to normal (for Subaru) consumption and I'm guessing she just added some without checking the level first at least once or twice.

Adding to this, I finally had a chance to ask my wife about it and she says the last time she put any oil in was about a week prior to this failure. She'd probably driven maybe a couple hundred miles in that time. 

[Koniko]

Forgot to post this earlier but I did actually did figure out what happened for anyone who was curious. I checked inside each cylinder with a borescope and found a broken valve in one of them. Destroyed the plug and at least one other valve, marred up the piston, and probably didn't do the cylinder walls or head any good either. Didn't bother tearing anything down after finding that so I still couldn't say specifically what the initial cause was,  but the engine is toast.

 

Edited September 21, 2022 by Koniko
Spelling correction

[Koniko]

[DougKelly20]

Thanks for following up. Would make sense that it turned almost all the way and then stopped in that case.

[silverton]

oh now that is some carnage!