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2008 Subaru Outback - Help me start this project right

Inherited an abandoned 2008 Outback, 252,000 miles. Don’t know what exactly was wrong except engine problems and it was towed home when the engine quit and sat ever after. It drove onto the trailer and drove off. I changed oil (synthetic) and test drove it about three miles when the engine lost power and started bucking severely - car jumping up and down trying to hold 20 mph from 35 - and then it died on the road and wouldn’t start again. There was no rattle or abnormal engine noise. A year later when I am ready to work on it, I charged the battery, started it, and the engine rattles like a rod bearing is shot or a lifter is collapsed. Oil is still clean.
Can a rod bearing go south that fast with no hard turns, taking it easy on a level road?
Also, I noticed a Check engine light, code P0113 which has absolutely nothing to do with the engine mechanical condition. How do I diagnose this fault between a bad mass air flow sensor, bad wiring (it all looks good), or a bad temperature sensor (high output)?
Also, does Subaru publish a factory service manual with wiring diagrams for the 2008 Outback?

I found an online service manual for $9.95, excellent buy.
The engine is shot, apparently the oil got low, they took a curve or whatever at high speed, pump sucked air, and all the crank bearings are galled and #1 rod bearing failed completely, #1 piston hit the cylinder head and broke off part of the upper ring land. I think the head is still good on that side, noticed a bit of galling on one cam journal, rest still looks good, left side head looks ok as well, so now I have some parts to sell. The parts cost to rebuild is looking very close to $2,200 cost of JDM engine.

David, you just inherited a very large paper weight. If you really want this back on the road I would suggest a used engine or just getting a rebuilt one.

A ten-year-old vehicle with a 1/4 million miles? With an engine knock? And a Subaru?

Sounds like a money hole to me.


It’s hard to diagnose an engine that won’t start. If you really (really, really) want to work on this thing, start with a compression test. It’s possible the timing belt has failed and there’s internal engine damage, and a compression test will start the process of convincing you to either give up or find another engine and rebuild it over the Winter and install it in the Spring.

I vote for the recycling yard.

So how long did it sit before you got hold of it? If you’re talking a year or two, etc then odds are the gasoline has turned to garbage.

Bad gas can also cause a rattle and I think you’re getting bit ahead of yourself with a factory manual and schematics. Odds are it won’t come to that.

Can’t be a collapsed lifter. This car has mechanical lifters.

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I have a feeling the right way to start this project, will be calling a wrecker. And will end with getting the salvage value at a junk yard.

The engine is shot. Compression was 90 psi on number 1, 200 on number 3, 165 on number 2, and 160 on number 4.
Also, when I changed oil, I put 5 quarts in. It only takes 4. I think I foamed the oil and killed it.
I am going to rebuild it. Can’t get a car with that good a body for the cost of parts to rebuild. I looked at used and reman, but they want way more than the cost of parts.

Compression was way down - 90 - on number 1 and only 160 on 2 and 4. #3 was the only one to hit 200 and it should be 210.
I put 5 quarts in when I changed oil. It calls for 4. I think I foamed the oil.
However, I am going to rebuild it. I have a shop and parts are way less than the cost of anything else with a body this good and everything inside works. It will be the first car made in this century for me. My newest is a '97 Avalon with 367,000 miles, same engine, same tranny, and rock solid reliability. Some heater controls have failed, but everything else works.

My thought would be to get a rebuilt engine, too many questions on this engine for me.

Id say put a used jdm motor in it …sell it and buy another Toyota.

Are you sure the timing is right on, the crankshaft and valve train in synch? If that’s out of kilter it could explain at least some of the compression results. So could valve clearance adjustments, but check that only after the crankshaft/valve train timing is right.

does not look to be the case

if compression was low on one side and high on another, that would definitely explain it, but results David reports are not like that

BTW, my first Subie I bough had exactly the problem you described: it had timing set incorrectly by 1 tooth on one of the sides, it resulted in around 30 psi compression drop on that side, was easy to fix, it was non-interence 2.2L engine

If you have the time and the place to work, and the skills and interest to give it a try, I can’t see any reason why you shouldn’t take a shot at a rebuild. Before I did that work, though, I’d put some serious effort into making certain the rest of the car is worth the effort. Obviously rust is number one, but these Subaru’s have complex power trains and something gone bad in there could really make the job a bust. If you could find a wrecked roll over Suby from the same era you might be able to swap out the entire power train.

The compression being so low on one cylinder only points to a possible tight valve; meaning burned. Considering the mileage I can’t say fixing the heads only.

If you build the engine be sure to not get aggressive with separating the engine block and be sure to measure the oil clearance on the main bearings. It’s ideal to set the center bearing up a bit tighter than the others.

The body and interior are in perfect condition.

  It was dealer undercoated and lived in eastern Washington (drier than California and much colder) until it died. 

  The miles are all from long distance driving to swim meets in four states - very little stop and go.

  I rebuilt Corvair and VW engines back in the sixties, but those were nowhere near as nifty as this 2.5i. 

  I have it out, I keep thinking this engine could be in an airplane if it had an inverted lubrication system. It reminds of aircraft engines I have worked on, precision parts, optimized for weight, etc.

  Subaru is definitely in the 3D modeling / CNC world.

Do you mean torque the center bearing a few pounds tighter than the others?

  As soon as I get off my ___, I'll pull the head and see how the piston crowns, cylinders, and valves look.

Can’t be valve timing, #1 is low and #3 right next to it is the highest one, 200psi, plus the engine has never been apart. The former owners always went to the dealer and were not afraid to stay on the dealer’s case until things were fixed to their satisfaction - the wife drove the car and didn’t like surprises at all … .

No. I mean by checking the oil clearance on the crank bearings with the use of Plastigage. Any service manual will show how to do this. It’s very simple and Plastigage is dirt cheap.

The reason for setting the center bearing up a bit tighter is because if the center bearing is too loose the engine may have a subtle thump sound at idle. It will run fine, but…

I would also suggest after torquing the head bolts that you allow the engine to sit all night and then retorque them again the next morning before instaliing the valve covers.
If you’ve done VW and Corvair you shouldn’t have a problem with the Subaru.

The pushrod Subaru 1.8 is a somewhat popular aircraft engine.

Start by disassembling the engine enough to verify the valve timing is correct. If that’s ok, next remove the head for a look-see at what’s going on there. You may get lucky and taking the head to a machine shop for rebuilding is all you need. If you discover there are problems in the lower part of the motor, you can get some price quotes & decide from that if you’d rather rebuild it yourself, or purchase a used or rebuilt engine. Lots of options to choose from. I expect you already know that there’s not much economic bang for the buck with doing any of this, and that the main benefit to you is that it will provide a fun and interesting project.


#1 rod bearing failed, piston beat the top land off against the cylinder head. Crankshaft is shot, new one is $351, pistons $67 apiece, rods, bearings, all the gaskets (that 2.5i has seals and gaskets everywhere: It’s like an aircraft engine!), just about adding up to a JDM engine. Anyone need cylinder heads, valve covers, small parts? I have some!