nvu

If it's just at the reservoir I'd rtv the mating surfaces. The copper washers are for the newer style reservoir.

push the piston 80% of the way into the block, tighten the compressor a bit more, tap around the edges so the compressor gets into the chamfer, tap the piston in

are you using the ratcheting sleeve compressor? place the piston face up on a flat surface, place the compressor over it and lightly tension it down making sure everything remains square. pick both up and put it them on the block, tap it so the skirt protrudes into the block and the rings are around the last tension band. lightly tap around the top of the compressor and tension a bit more. make sure it's squared and centered. the piston should slot in with moderate tapping.

Center diff takes the brunt of the mismatch. In a safe place, drive in figure 8's and see if there are any odd noises under the car. Center diff failures are usually a binding/release feeling, then quick knocking sounds, then catastrophic failures that could lock all 4 wheels. It's probably safe if there are no noises or binding.

For composite gaskets it wouldn't do much as they fail the rubber/graphite breaking down and eventually coming apart. Moving the thermostat to the top has the risk of it never opening if there's a pocket of air big enough to dry it out.

No

R180 only found in sti, and mated to the 6spd. Will need bigger axles and the bigger hub knuckles from an sti of that era. To drop in and replace an r160 you'd have to frankenstein some axles and possibly slot out the driveshaft flange. I'm only familiar with the gc/gd era up till 2007. Maybe later models have something what would drop in.

it's a bit misleading, they are and aren't depending on the years. 05+ sti's changed to 115x5 hubs and cartridge style bearings. They are no longer press in bearings. 08+ wrxs changed to cartridge like sti's. so, 04 sti, 07 and earlier wrx are exact same knuckle/hubs as base impreza. no differences there, only beefier axles or different brakes on the better models.

Cut up a credit card, jam in between seal and snout, pry all you want with screwdriver.

Might be a weak tensioner, it shouldn't move at all when the engine is running. Half a tooth off on one side isn't a big problem.

From the 02-03 factory manual

Another vote for tensioner

Not sure if it's necessary, but move the cam and crank sensors over too. One less thing to troubleshoot.

Is it a push clutch transmission? Could be cracked clutch fork if so.

No experience with automatics, I went from a cable throttle turbo to dbw turbo; same car, same manual trans. There's somewhat of a rev hang with the dbw when shifting gears. On the cable engine, you clutch in, let off gas, and shift. On the dbw, if you do the same thing, depending on how hard you're accelerating, the rpm would stay the same or even shoot up even though you released the gas. Not a big deal, you just learn to let off the gas before clutching in hard acceleration. I was annoyed for a month or so. With the manual I don't recall any twitchiness at the low end, but then again the rev hang bothered me more.

Some smoke in that rear area is okay, that's what the pcv is supposed to remove while idling. With the engine hot, rev it aggressively couple times, as long is it's not spewing out a constant trail from the oil filler it should be ok. Was the old one clogged? Shake it, there should be a loud and metallic clack like a paint spray can. A dull thud would mean it's starting to clog up. You'll still have to address that oil leak, take off the cam covers. They should be 10mm bolts. Being that old and oil soaked, expect some nuts to be seized and end up breaking the plastic they're molded into. If that happens, just proceed with the rest of the bolts and pry the cover off. Only the side covers are removable, the center one can't be removed without taking off belts and crank pulley. Flashlight and phone camera can be used to inspect the center area.

Maybe excessive blowby and/or clogged pcv? Drive around and get the car up to temp, take off the oil cap and rev the engine a bit. If you see smoke coming out of the oil filler neck it's blowby. It's rare to see the oil pump seal leak.

I've disassembled outer joints by holding the entire shaft vertical, outer joint pointing up. Smack it down on a wooden workbench where the cup catches the edge and the weight of the rest of the shaft pulls it out of the c clip. Even easier if you have a V corner workbench. Also... mind where your toes are.

Grease or oil up the inside where it meets the shaft. Lightly grease or oil the outside so it doesn't pinch while going in. I prefer pressing as hard as possible by hand until it's centered, tap until flush with the head. I had an older ej22 head with a chamfered hole on the driver side. In this case, using the old seal flipped around would allow me to push the new seal further in. Don't bottom it out, the goal is to push the seal in just enough so the outer area makes full contact in the metal hole and holds tight. Oh the snout with the oring, silicone grease or oil is ok.

No fuel filter, clogged injectors.

The screw with the gear teeth should be the adjustment screw. If it does nothing, someone turned it too much and broke the plastic gears inside.

https://parts.subaru.com/a/Subaru_2001_Legacy-Outback-Wagon-30L-AT-4WD/_51505_6029304/ROOF-RAIL-ROOF-SLATS/B12-922-02.html are these it? looks more than just glue.

Get it fixed, the tires will wear unevenly. Also check if you have directional tires, not only is there an inside/outside to those, but also a directional rotation arrow. Those would come in sets with 2 left and right sides.

no, the stud pattern is 5 x 100mm if I recall. 4.5" would be 114mm

Hi again, from my previous post, I have a 98 obs with a bad shortblock. The plan was to look around on car-part and visit the local yards for a complete EJ22 but so far that's been turning up empty. I do see a lot of EJ18 SOHC's around, that seems a little too small for an awd wagon. Still searching for the EJ22 in the meantime. Are there other engines that will work with the 98 OBS ECU? The other option is refreshing the heads and putting another shortblock on. I have one from an EJ257, the heads are the EJ22 with external headbolts, single port. Will this combo work with current ECU? This is a california car so the ecu needs to remain original for smog.