Numbchux

I've bought a couple Spectra Radiators with very good results.

This. The cast alloy and plastic ones use countersunk hardware because the plate is much thicker. The plate steel ones use a conventional bolt. If you've got a dealer nearby, go spend $5 and get the right ones. The dealer I worked at always stocked a few sets as we would frequently retrofit the new plate in place of the plastic ones.

There's probably a heat shield towards the front that can make it a little tough, I throw that in the scrap. 4 bolts (you'll need a decent 12mm box wrench, as there's not enough room for anything larger, and a fair bit of force) at the rear diff, and 2 bolts that hold the carrier bearing to the body. Then snake the whole thing out towards the rear (there isn't enough room to drop it straight down without removing the exhaust).

Those are all reliable components. The reliability will be most effected by the build itself. In this project, you will be removing almost every mechanical component in the car...so it'll be on you to make it reliable. The biggest thing will be the engine wiring, make sure it's clean, all connections are moisture and vibration-proof (I use only Molex Perma-seal butt splices), that nothing can chafe. You will also have to replumb the fuel system, so again, make sure it's done right, and you're not going to have problems down the road. Do not assume it'll be a completely reliable car right out of the gate. Don't take it on a road trip a week after getting it running. Issues will present themselves, you will have to limp it home, maybe towed. If the 81 has A/C, it'll just be a matter of making custom lines to plumb the EJ22 compressor into the EA81 system. If not, you'll have to retrofit an evaporator and stuff into it.....I don't know. Easiest is to just use the EA81 crossmember, front suspension, and axles. You could build your lift blocks to adapt the wider EA82 crossmember onto it, and then use those components, but IMHO that's more work than it's worth for a lifted build. I don't find the EA81 manual rack to be a problem with big tires. I have 29" tires on my Brat, and it seems to work well (not street worthy, don't think I've ever had it over 15mph). I had an EA82 with 29" tires that had a power steering rack that someone had deleted the pump, that was annoying. This would be the only reason to use the EA82 crossmember, as getting an EA81 power steering rack is very difficult. EA81 fuel tank doesn't have the same baffling as a fuel injection tank would. So you'll probably have occasional fuel starve when the tank gets low and starts sloshing around. The correct fix is to add a surge tank, but I just would fill up a bit sooner. There are a couple hurtles of using the EA82 5-speed transmission in the EA81 body. Custom/modified crossmember and driveshaft, IIRC. I haven't done it, but it's been discussed here many many times.

Seen it. Not uncommon for the tensioner bolt to strip out, luckily that bolts into a separate part, not into the block.

And? How did the old fluid look? Was the level low? How much material was on the drain plug magnet?

I don't know the volume, and I won't help you put snake oil in your system. Don't do it. Fix it right, or keep topping it off. A couple ounces in a year is not worth causing more damage by pouring syrup in there.

Ujoints are almost always worse under load. But I wouldn't hesitate to drop the shaft and feel them. Hardest part of the job is getting the car up high enough to get under there (I usually drive one end up on ramps, and then jack/stand the other end). Does it get worse the longer you drive it? I've had a sticking caliper slide cause a vibration at speed once that brake gets hot. Also check all suspension bushings. What axles were used? I've experienced many an aftermarket CV axle cause a vibration.

Huh? Something was changed, and something changed, so they clearly can't be related? What kind of tires were put on? Are they all the exact same? When I was at the dealership, we bought a 4.11 Subaru diff from a junkyard for a customer car, and it ended up being wrong (I think it was like a 2010 Legacy MT that used different axle splines). He said they usually throw away the common 4.11 diffs, and it wasn't worth the cost to ship it back to him. I still have it...just in case.... What I'm saying is. A. It's very unlikely that it's your problem unless the fluid has leaked out B. You should be able to get one cheap. Don't look on ebay, as shipping will kill you. www.Car-part.com and you can find one at a local yard for much cheaper.

WJM (RIP) wrote a fantastic article for SubieSport Magazine 10+ years ago about his RX, running the EA82t on MS+EDIS. Look for some of his old posts, he was doing some serious work and a lot of documentation.

I'm sure I'll be in town in August for Ojibwe Forests Rally.

Sounds like from Tire Rack? We ordered snow tire sets from them fairly regularly when I worked at the dealer. It's a chunk of change, but it's really convenient to receive them ready to bolt onto the car.

Other hole is a stud, with a nut on it. not a pin

I don't know the Forester trim and options at all, but they started trickling rear LSD in with cold weather package outbacks about that time... www.Cars101.com will have detailed standard/options lists that will tell you if yours is likely to have the rear LSD.

Plug an OBD reader in and read the coolant temperature, and compare it to an infrared temp scanner pointed at the coolant bridge (if you don't have these tools, combined investment of $20-30 on amazon and invaluable diagnostic tools). If they agree, that's not your problem. Then connect the test mode connectors to make sure the circuit operates as it should. A/C will warrant fan operation, and defrost engages A/C. Depending on the conditions, it's not improbable that the engine really is warm enough to warrant low speed fan operation.

Which ones were that? Not in the last 40 years. I know of plenty of people running 8-bolt transmissions with 4-bolt engines that leave the lower starter bolt out....but you couldn't pay me to do that on a car I had to rely on.

I ASSume 2.5, CVT? Does it go into Park (engage parking prawl)? What fluid did you use, and did you put it in the right place (fill plug on the side)? I know these can be a bear to get all the air out (best done level, warm and running, which is hard to do without a hoist), but I wouldn't think an air pocket would default to drive.

You've got a bad connection somewhere. I've seen it a few times. My XT6 was a loose bolt between battery cable and terminal, Loyale was a melted connector at the ignition switch, old Legacy someone didn't put the main ground wire back on when replacing the starter. Check the main battery cables (positive to the starter, ground to the starter bolt). Make sure they're in good condition. Wiggle them around and see if they feel too soft or too hard (I've seen moisture get inside the insulation and corrode the copper from the inside). If those look good, you can buy a high-amp relay, and install it between the battery and starter solenoid to isolate any issue with the ignition switch/wiring/connectors inside the car.

Subaru automatics (there are some premium models with VTD AWD that are different, but definitely not yours) are VERY front wheel biased. Drive to the rear has a noticeable delay, and as the clutches that drive them get worn it gets worse (my XT6 requires considerable front wheel spin to get the rear to engage at all.....not ideal). Manual transmissions use a much simpler AWD that sends the power to both ends equally and has a viscous LSD to prevent slip. The Forester might have a rear LSD, whereas the Legacy definitely didn't, but that'll be a pretty small difference. So it's not a Legacy v Forester thing, it's the transmission type.

PCV hose. If it leaks, you get a post-MAF air leak, which will cause running issues. You can replace it with generic hose, but be sure it is PCV rated (oil and vacuum resistant. coolant hose will break down and become gummy).

It's possible the worn brushes on the motor were knocked clean as you replaced it (for the first month or so of driving my winter beater Outback this year, I had to smack the blower with my snow brush to get it to start working in the morning), just like smacking a bad starter. Or, your problem is actually a bad contact somewhere that you jostled when replacing, and it'll return...

I haven't been doing harnesses for many years....not worth the time. SJR still lists it on his site: https://www.sjrlift.com/collections/engine-swap/products/wiring-harness-thinout-ej-swap

Grain of salt: my expertise is with EA82s, but off the top of my head I think EA81 is the same or similar....but I could be wrong. You can hook the EJ temp sensor to the Brat gauge and it will read low, but still usable (you sort of have to mentally re calibrate what normal is...). You can use a resistor to fix that reading (details in the writeup). EA sensor uses larger threads than the EJ, so can't use that, and I don't think there's enough material to drill/tap to the larger size. Also there are universal sensor housings out there that fit inline with a radiator hose. If you go aftermarket (digital or analog), you can reuse that wire in the EJ harness for a clean installation. Tach is just a matter of hooking up the correct wire from the EJ ECU to the Brat gauge. Speedometer is mechanical. I know that an EA82 cable will work with an EJ transmission. People have swapped EA82 and EJ transmissions into EA81s many times, and I don't recall any discussion of any difficulty with cables there....

Very little will be identical. Phase 1 vs 2 engine/transmission. Different body style. Brakes are the same. Front struts, knuckles, control arms, axles will be similar (I think there's a difference in ABS sensor). Driveshaft will be the same if it's the same style transmission. Exhaust will be similar. Fuel pump is different. The BE/BHs don't seem to be plagued with filler neck issues. But the '00-'01 ones are susceptible to rear subframe rust. I just replaced that on my '00 330k mile OBK, and the filler neck looked great.