Numbchux

Probably best to be familiar with the diagnostic mode of the Auto A/C, so some tests can be run when it's acting up.

Feel the heater hoses. Hot upper hoses and cold bottom means the thermostat is almost certainly working (at the very least, there isn't any flow through the radiator, but if the coolant level was low or had bigger circulation problems, the engine would likely be hot and the upper hose wouldn't). If one heater hose is hot, there isn't flow there, likely core is plugged. If they're both hot, then it's an issue with the control (air is being diverted around the core, it's not calling for heat). There's a diagnostic procedure for the auto temp control in the FSM, I haven't had to mess with it on our '00-'04s, and I avoid the 05+

Yep, that's the tone wheel for the crank angle sensor. It's junk now.

Well, the exhaust and port is similar to the EZ30, but beyond that, the head has nothing in common.

Very interesting pictures. It looks as if the head casting might be the same, and just the ports machined out differently.

You're forgetting the '04-05 EJ259. Single port exhaust similar to an EZ30. AFAIK, the only thing unique about the 259 is intake and sensor related. The Block and probably heads are the same.

AWIC leakage is pretty rare, certainly on anything with any quality. But, they are a much more complicated system, and getting core/exchanger/pump all working together is kind of a challenge. I highly doubt you're making enough heat on an EA82t to justify all that. Just a simple early WRX one would be perfect.

Needs a whole control arm? If you're desperate, the dealer will be the most accurate way. They come with the ball joint, where aftermarket typically does not, but they can usually be had in a day or 2, and you'll be completely sure it's correct (looked up by VIN).

For the record, I took "back up" to mean reverse. But this is a much larger circuit, providing constant power to many circuits, and I don't think any of them are in the rear hatch.

Back up lights are in the hatch, right? These are notorious for having damaged wiring between the body and the rear gate. The dealership where I worked stocked rear gate harnesses (MSRP was about $85, I think there are 3 different part numbers, use your VIN to look up). Obviously individual wires can be repaired, but this will not be the first time you have it happen.

Oh yea, same idea on basically any vehicle with a return-style fuel system. Returnless cars just have a spring, no vacuum/boost reference (as the regulator is located in the tank, not practical to run a vacuum hose back there).

I've seen several times, all on mid-'90s EJs. Pull the vacuum hose and there will be fuel in it.

Was it exceptionally cold that day? How many miles are on it? How's the maintenance been (specifically, spark plugs)? And then yea, I'd be inspecting that fuel pump cap: https://www.subaruoutback.org/threads/symptoms-of-fuel-pump-o-ring-problem.41182/

Yep, the 6-cylinder will mechanically bolt into the 4-cylinder car, they are the same chassis. But ALL the wiring will have to be changed, which means the dash has to come out. Having done dozens of engine swaps, and recently replaced the rear subframe in my 330k mile 2000 OBK, the subframe is 1000x easier.

Yea, the ATV ones (which are lighter and have a much larger customer base) are several thousand. A small run of heavier duty ones are probably going to be more like $5k. You could be a real offroader for that. There was a video floating around of an EA81 hatch with tracks on it years ago. I assume they were purchased for a 6-lug truck and bolted onto the Subaru for laughs. Those are more like $20k for a set.

OK, yes, Engine control wires absolutely go through the SMJ on those. To be honest, I never worried about the shielding. It should run back to the ECU (and grounded through the ECU), I don't recall noticing that path being broken in a harness thin, but I may have missed it. In practice, I've not found this to be terribly crucial. In one case, on my Loyale, I was having a bad connection between ECU and crank sensor, and I strung 2 pieces of new wire from the ECU to engine harness. It was supposed to be temporary, but I never had an issue, and never changed it (It probably lived for 5 years after that).

It's theoretically possible, but AFAIK no such product exists, and if it does it will be a $5k+ set of rally coilovers.

FYI, I haven't responded because you haven't posted WTF you're working on.

03 is likely second gen (certainly is om the US, other markets generally got them sooner). You'll need a turbo LHD engine crossmember (should be able to use a WRX one), but other than that, all major mechanical parts should bolt up. Wiring will not be plug and play, different body styles and different driving positions will make sure of that, but with good diagrams and good understanding of them, it could be modified. Dash will have to come out of both for the wiring conversion. Big job, likely makes more sense to sell what you have, and just buy what you want. But each to their own

Every brand carries an ATF that is Dex II compatible, usually labeled Dexron III or Dexron/Mercon or Dex/Merc, Most offer synthetic and/or high-mileage options, although if you're considering synthetic, I'd just get Subaru HP fluid. IMO, pick your favorite brand, or shop around for price, and buy any of the options that say Dex II or III on the bottle.

Yep, that switch is definitely leaking. Aftermarket ones are about $8, Subaru MSRP is $22.75. I've had a couple aftermarket ones leak in pretty short order and have been putting Subaru ones in. Even used an OEM Subaru one in my Celica when it began to leak (I was working at the dealership at the time, so my price on a Subaru one was cheaper than a Toyota one).

Yep, manually selecting 1st makes the duty C logic a bit more aggressive.

Yep, EA82. EA81s have the disty on the front. EA81 would be 4 speed, very different trans. Being that it's carbed means I think it has to be '85-early '87, which likely means narrow trans tunnel, so the trans crossmember might not fit. But everything else should be good.

ASSuming your donor is a non-turbo EA82, and your Loyale is already 4WD. If it's turbo, it won't be D/R unless it's an RX, which is it's own can of worms. Trans and crossmember, starter, flywheel (you'll need a clutch kit, too, but get a new one), flywheel bolts. Pedal box, clutch cable, shift linkage, center console (the GL has a much nicer center console, but it won't have space for the automatic shoulder belt retractors in the Loyale, I don't remember how that all works out, I think I'd already chucked the auto belts by the time I did the center console. At least the front half of the driveshaft Probably rear diff (EA82 D/R will use a 3.9, IIRC the 3AT uses a 3.7). The only way a non-turbo EA82 would have a rear LSD, is if it's been swapped in it. Don't need the cluster, in fact, it's a pain to swap it, as the wiring is completely different. Don't need the master cylinder unless you plan to retrofit the hill holder, and even still, you can just plug one of the ports on the master.

ASSuming it's not an H6 VDC model, that will have MPT AWD, which is extremely FWD biased. Hard to quantify how much delay is "normal". It always feels like a week to me (why I'm obsessed with VDC cars...), but I've spent hundreds of hours ice racing. Put the FWD fuse in and drive it around for awhile, that will completely disable the rear drive, and give you an idea of how much power is getting sent to the back. The rear drive is just a set of clutch packs. They can stick and wear. Not a terrible job, doesn't require pulling the transmission.