DaveT

The 2.5 dohc blew headgaskets a lot. There is a lot more info and details in the newer generation sub forum. I never had one, so what I have picked up came from those threads. It's nearly unanimous to stay away from ej25s. The mod I have considered is swapping an ej 2.2 into a Loyale ea82 which is a 1.8. It's something like a 50% HP increase. It's been done. More power upgrade than that, you'll just spin tires all the time and /or blow the rest of the driveline. Somewhere I had found a list of Subaru engine models and thier HP ratings that made it easy to compare. The SPFI ea82 is noticeably more power than carbed ea82. Iirc the main difference between EA81 and ea82 is the overhead cams. Some have put the SPFI onto ea81s.

Typical indication of alternator failure.

The ej25 is notoriously unreliable.

Correction - 6500rpm redline. They just don't really want to get there.

Obviously don't go too close to that for too long.

Ah, that's different - ea82 red line is 6000.

I don't really do offroading. But my ea82 powered 4wd 3 speed automatic wagons see 5000 to 5500 rpm getting going in 2nd onto the highway. Keep the cooling system good, use good oil.

If the idlers have anywhere near 100k miles, replace them all.

I have a moderate amount of experience looking at engines. Low rpm high tourque ones have noticeably wider connecting rod and crank bearings than high rpm low torque engines. If I remember correctly, EA81 lower end is very similar to ea82. Ea82s start making power around 3500 rpm. And perfectly happy spinning 4000 on the highway.

From all the various threads I've read on here, the easiest, lowest cost, reliable, significant hp upgrade is to ej 22 it. None of the options are easy. I doubt turbo or supercharger would be cheap. Both increase stress on the stock lower bits of the engine, which are solid, but that is why they are reliable. There are a few things that can be done that are either expensive or time consuming to get small increases. Side note, these engines make power at higher rpms, so downshifting is preferable to lugging.

Under the hood does not seem like a good idea to me.

you need to connect everything engine electrical related. Except don't really need the alternator. When I did it, I had a spare transmission, so I could mount the starter also. Ran water from the garden hose through the cooling system instead of a radiator.

Verify 1,2,7. Then thermostat. Radiator -- flow and fins.

Trying to think of what might cause both supply and return to get hot.... High side seems maybe low? I'm thinking the compressor is working, since the work is showing up as heat in the lines. The A/C section of a factory service manual has a LOT of detailed troubleshooting information. IF the condenser was not getting sufficient airflow, the system would be unable to cool properly.

The thing in the picture is the fuse able link box. All of the high amp circuits go through it. You would be best served to find a factory service manual for the full schematic and all the section pieces with details. There may be a link around for an online one, or ebay. It would help to know if the engine is SPFI or carb, and year.

Usually there will be a build up of gunk where the leak is, if it is so slow there is no liquid evidence.

With a known coolant leak, I would be checking it a lot more often than that. A quart low is pretty dangerous. I have no experience with the 6s. But it is typically death to headgaskets to overheat while low on coolant.

Double check that you found all of the bolts. There are a couple of sneaky ones.

I would not use the overheated water pump. It's been over temperature, and run low on coolant. How well does the seal stand up to that? The last time I bought one, the best quality one at NAPA was around $50.

I use Amsoil. It made a huge difference in my 76 & 78 4 speeds in winter. With regular gear lube, it would barely shift from 1st to 2nd the first few time on cold mornings. With the Amsoil, it shifted the same as summer even in winter. Yes, it is spendy, but you can run it for 100K miles.

With some luck, someone on here may have seen both. There are factory service manuals online, digging through those would take time, but they will have the different versions, so you could compare. The only 1st hand experience I have is with Loyales - I have a CA one, and a few 49 state. On those, there is one extra sensor to measure the EGR temperature. Everything on the EA82 engine is identical except the intake manifold.

I recently sold our 2001 Forester. If the timing belt and all the idlers have not been replaced, it is time. Water pump might as well also. It is also likely to need head gaskets soonish, due to mileage and time passed. If you have access to drive it a few times, you could do this: Check coolant level cold, in the recovery tank. Check that there is little to no air in the system by squeezing the upper hose sharply. If the coolant isn't full, and near the mark in the bottle, correct this. Take a drive. Next day, re check both cold. Take a drive. Once fully up to temp, If there was little to no air in the system, watch for steady small bubbles in the recovery tank. They can be very slow, so watch for a minute. Steady bubbles = head gasket failing. It will get worse, but you can get away with it for a while, depending. If coolant is "disappearing" you have to find the leak. If the engine is run over normal temp while low on coolant, this will damage the head gaskets, and lead to failure, sooner or later, depending on how badly over temp, time, etc. On a car this age, be sure to check the radiator condition carefully.

Yes, if the system was already opened to fix what ever caused the lost refrigerant, there is nothing in it to recover. All you need to do at that point is to draw a vacuum to remove air and moisture, check for leaks, then charge.

I suspect a vacuum would pull oil through the crack. I never had one tested. I have had only 1 head since 1988 fail due to a crack that opened between the coolant and the exhaust port. I don't know if it started from the typical between valve crack.. I do know that it was part of an engine that was run hot with low coolant a few times. (worst case I ever had ) it was the only Subaru engine I've seen where a blown head gasket put coolant into the crankcase. It ran fine for a number of years after I resealed it, before the coolant leak problem developed. It also burned oil like crazy, I suspect the oil rings got ruined. 1 quart per tank of gas , but it passed emissions every time. Since I figured it was toast, I just added used oil, old oil, surplus old atf, every other half quart, mixed with cheap new oil. I only stopped running it when the coolant crack got so bad that abut 16oz of water would drip through while it was parked at work. I ran it with a zero pressure radiator cap, otherwise it wouldn't have kept coolant long enough to get anywhere. So as long as the coolant jacket isn't compromised, and your heads haven't been badly overheated, they should be reliable.

Knock off the loose stuff, apply Waxoyl or similar penetrating /greasy undercoat.