97 Legacy Outback - fearing the worst

[thedrew]

Hey Guys,

 

My new to me 97 Legacy Outback had a major fail today. I'm still trying to sort out what the problem is and how screwed it is.

 

162k miles, 2.5 DOHC engine. Unknown history. Been driving great for the past two weeks, then today it died.

 

I was on the free way and all of a sudden it lost power. Related or unrelated, I heard a noise kind of like I was running over something and stuff was being kicked into the wheelwells. Temps were fine, no CEL.

 

Pulled over, tried to restart it turned over for a sec and then stopped. Tried again and then like the starter was stuck. Engine would not turn over at all.

 

Towed home and I drained the oil, no shimmering oil or bits in it. I peaked at the timing belt, still intact.

 

I then tried turning the crank, would not go forward, but would move backward. I rotated it backward a few turns and now it turns freely.

 

I cranked the engine and it wont start, and it popped a few times up the intake it seemed like and got smoke out the intake.

 

Should I start shopping for a new engine?

 

Other Ideas? I'm pretty frustrated and am giving up for the night.

[lmdew]

Pull all the Timing Covers and check to ensure it's properly timed.  Lot's of time the belt will hold, but timing jumps.  I'd do that first so you don't bend valves.  Hopefully you did not bend any yet.

[Bushwick]

Sounds like it lost a valve or bent one. I wouldn't try starting it anymore as-is. Pull the heads and inspect since it was locked up. If the pistons aren't damaged, you might be able to get away with swapping another head on (might just need one) and a new belt and it'll run again (if you end up going this route, make SURE to have the head inspected as it might be warped). On the other hand, if you stick a new belt on, try starting it, if a valve was bent and is sticking, it might get unstuck and snap off, and you've just destroyed the piston, connecting rod, etc. It's also possible a valve won't be working, so you need to inspect.

 

 

If you decide to do a belt and not pull the heads, pull the fuel pump fuse and do a compression test. That should tell you if a valve went and will hopefully narrow down to one side of the engine or the other with a 0 psi. Obviously if that happens, you'll need to pull the head. Just please don't throw a belt on and try starting it as you might go from having an engine that's able to be saved, to one that'll have a hole punched in the piston.

Edited December 3, 2014 by Bushwick

[MilesFox]

Perhaps the idler cog is falling apart causing the belt to skip. You might be lucky as i was when i picket up a 98 legacy outback by just re-aligning the belt and replacing the idlers.. Check the belt rotations and refrain from cranking the engine until you check it out.

Edited December 3, 2014 by MilesFox

[thedrew]

So I'll pull the timing cover, check timing, and do a compression test.

 

If no side is 0psi, try to fire it up?

 

Otherwise I'll probably pull the engine and go from there.

[thedrew]

But the engine was hitting something, and it would not turn over.    THAT is bad.   Have other people experienced this and the engine was OK??

[thedrew]

also, how much can the belt slip before there is a piston/valve collision?

[Bushwick]

The compression test would tell you if a valve bent and isn't closing all the way (as would a micro camera that can be fed into the cylinder plug hole), but you'll need to realign with a new belt if the old one indeed stretched. You'll need to hand crank the engine with a 1/2" ratchet or breaker bar through a complete firing event of ALL 4 cylinders BEFORE cranking it, (so that means the compression event then the exhaust event) so it'll need to open the intake valves then the exhaust valves for each cylinder. If nothing is heard or felt grinding, clanking, binding, etc. (with vehicle in "N" and plugs pulled, it should spin fairly easily) you can probably try and test compression on each cyl., 1 at a time.

 

I think it might be possible to get 2 cylinders on one side of engine near bottom to halfway of the stroke, which would allow you to hand turn each cam sprocket as it shouldn't hit the cylinder. That might give you an idea if it binds badly if a valve bent slightly and is sticking. Worth a shot. Maybe someone more intimate with the DOHC can comment.

 

 

IF it passes a compression test and no odd sounds or resistance was felt, you can try starting it with a new belt. If you hear "popping", you have a bad valve. Suppose it's possible it could drop a rocker arm too.

[Bushwick]

But the engine was hitting something, and it would not turn over.    THAT is bad.   Have other people experienced this and the engine was OK??

 

If it was indeed valve to piston bind, it's probably shot. Even if the engine was OK after stalling, cranking it can bend the valves if jumped bad enough. I'm guessing people that actually managed to fair OK after a timing belt event either got VERY lucky, someone swapped their engine before they bought it with a non interference engine, or their problem was with the actual idlers seizing up.

also, how much can the belt slip before there is a piston/valve collision?

 

Not much with interference engines and sometimes not at all. 

[MilesFox]

in  my example, the driver side cams were in phase, and the passenger side was 1/4 turn out of phase for the intake, and half a turn on the exhaust. I would imagine if it was any more there would have been collision. From what i understand with a DOHC is the valves can collide eachother.

[86BRATMAN]

Hope it doesn't turn out to be like this one.