Subaru engine ring failure

should i proceed with this repair. i have a 2001 subaru outback that recently developed a misfire. this was traced to a fouled #2 plug and leaking head gasket. in the course of pulling off the head the mechanic found a scored cylinder and now says the engine needs replacing. the motor has 140K on it. is it worth fixing or should i just do the head gasket job and take what comes? i would like to continue running this car. not long ago i replaced the transmission and clutch. eeek! thanks

If you have a scored cylinder and fouled spark plug, you probably will not get much more service out of that engine with just a head gasket replacement. With the head off the mechanic is not going to be able to do a leak down test which would determine the status of the piston rings on #2 cylinder and the scored cylinder if it isn’t #2. If you went ahead with just the head gasket replacement you will probably find very low or nonexistant compression on the scored cylinder. When these engines overheat it is possible to warp the cylinder block, making the cylinders out of round, and breaking rings. The broken rings score the cylinder wall.

If you plan to go ahead, have the mechanic measure all the cylinder diameters in multiple directions and points to see if it is out of round. It is probably poor economics to try a rebuild because the engine has to come all apart and even if you rebore to get the cylinders straight, the warpage will surface in other points (bearing saddles, case seams, deck surface flatness, etc.

Your best bet if you plan to keep this vehicle is install a low mileage used engine, maybe a Japanese import used engine. There are companys that can supply low mileage engines from Japan at a fair price.

Hope this helps.

Having a scored cylinder means the engine needs to be completely rebuilt and you should not do head gaskets only. It’s just asking for trouble.
Either rebuild the current one or replace the engine with another. The latter is usually more cost effective since scored cylinders means the block will have to be bored for oversized pistons, bearing saddles line-bored, etc. and this is going to get REAL expensive.

its reassuring that this is what my mechanic recommended too: a new short block from subaru and then re machining of the head. i thought subaru boxer engines had greater longevity than this.

There seem to be a lot of Subarus of similar vintage here with head gasket failure.

i’m wondering if the two issues can be related or is it just bad coincidence? the car never overheated, never was run without adequate oil.