1 Lucky Texan

first, I HOPE he checked his engine oil level. perhaps checking voltage at the battery while idling would be good - to confirm he doesn't have low system voltage. Having a mechanic confirm he actually has low oil pressure - vs an intermittent sensor or other electrical problem - would be the best place to start. Those oil pressure swiutches/senders come on at about 3psi I think ! If you want to risk losing a little time and money, the pressure sender is located sorta under the alternator I think. Not hard to change. You can probably do a search for pics - might even find a youtube video. if he actually has low oil pressure - it could be from extreme wear on the bearings, it could be loose screws on the oil pump's backplate, dented oil pan/cracked oil pick-up tube, a few different things. edit - beat by my slow typing!

first, diagnose the knocking, a weak timing belt tensioner can mimic a knock. The timing belt SYSTEM should have been done at 105K miles. If only a belt was done instead of rollers an tensioner, the tensioner could have failed.

destroyed rear bushings on the lower control arms will thump - but not usually in-sync with rolling.

look around the steering shaft u-joint. i have read of it abrading through a wire harness.

broken axle?

He says it's a FWD trans so, no rear diff or driveshaft.

If it's like my 4EAT but just without the tail section then yeah. technically, it's 2 units put together but no one 'rebuilds' the diffs (NOTE, that's not say some kinda seal or bearing at the axle output can't be repaired - but it's still tricky I think getting the bearing preload back to factory setting) - so, you might check LKQ and car-part.com for a used trans. KInda suspect the FWD version might be hard to find but, i haven't looked.

just my opinion; 1. go with it if you feel 'pieces' won't come off. If it's blemished a little - even deformed a little - it may resume it's molded form after a little heating. Maybe leave it on for the stove-top test even. polymers often have a 'memory'. Plus, seems like worst that might happen is some slight amount might bypass around the seal - no different than the jiggle pin. But you don't want chunks of it to come off! 2. Read those jugs text. I suspect it's OK to mix them. DexCool is often the bad one to be avoided I think. glycol based coolants should be able to mix. many people DO feel you need certain additives and low-amounts of other components but I think both those brands have been used by subaru owners. I'd risk it. Is it 'ideal' no, but, shouldn't be 'catastrophic'. 3. I don't think I'd use an entire bottle of conditioner. Just an amount proportional to what's being put in - maybe 1/2 bottle? I like to clean-out the overflow bottle - shake some ice cubes back and forth in it, rinse it out. Cut the little tube's bottom at 45* angle. Use a coupla small zip tie on the other end to create a good seal on the nipple at the radiator's neck. Inspect rad cap - replace if old. I like Stant, some folks insist on OEM.

the metal is thin, but as I recall, it seemed strong as fair mentioned. you could test the t'stat in a pot of hot water. opens at 171*F or so. (never create a situation where any animal or child/person could ingest coolant - permanent kidney damage and perhaps death will occur - no open drain pans a cat or dog could get to, etc. ,wash things thoroughly after stove top test)

I just mentioned is as a possibility. doesn't mean that's what happened.

pan? example, pinion turns ~4 times against ring gear in diff. (like 9 teeth on pinion against 37 on ring = 4.11 final drive) I admit to being ignorant of specifics of the FWD transmission but, on my car, the front differential has a separate drain plug with a magnet - maybe inspect it for big pieces? 4 vs 1 time per rev :example, pinion turns ~4 times against ring gear in diff. (like 9 teeth on pinion against 37 on ring = 4.11 final drive) maybe output bearing on side of the diff? that might be 1 time per tire revolution. if you could get the car up to AWD Tuning in Flower Mound, I bet those guys could diagnose it. I just really am throwing out possibilities - fairtax has the experience here. If you rule out bearings and axles - diff/trans is about the only thing left. If it helps, axles can be swapped side-to-side.

fair - could that install have bent/warped the t'stat enough to prevent opening?

are you still getting all the same blink codes you listed? on something as old as 92, I'd be tempted to put in a knock sensor and maybe a crank position sensor but, maybe the codes will point to something else?

just ducking in to mention I recently chaged the coolant and 3 big rad hoses on my 03 H6. first, draining it made a big mess - next time I'll try to position receptacles better. Someone mentioned hose clamps. A brand GEMI was mentioned in another thread and I bought some from Amazon - they are very nice, narrower that typical screw-type and the edges are rolled up. so, you might check them out. (diameter ranges listed in mm)

plug wires?

year? miles? general condition? what brand plugs/wires? Subarus are picky in this area.

none of us would have been likely to use Omnispark or most other aftermarket wires. perhaps we were just holding our breath hoping you'd report good performance? If you have the old wires, you could put them back on as a test but, seems like they are pretty old. OEM wires really do seem to be best. Perhaps 130 miles is what it took to oil-soak the new boot - maybe shorting high voltage again? any codes stored? um, any correlation with fuel level? maybe you have a fuel supply problem.

that's a real issue. that light comes on at 2 or 3 psi ! is the oil pan dented? how many miles on the car? any engine work done? there's an o-ring in the pan that I think can cause problems with pressure. Also, it's possible, though rare, the pick-up tube is cracked. maybe the pump has loose backplate screws?

have you checked front diff fluid level or pulled the diff's drain plug to inspect the magnet for 'pieces'? kinda wondering if you think it might be happening about 4 times for every tire revolution - or 1 time. any sense of either of those?

is the trans pan dented?

whoa ! awesome find

yeah, I could see nozzle metal abrading and building up there, never really thought about it before. considering all the vehicles those nozzles visit and hanging around outside all the time - they also could easily leave something behind that might compromise a seal i guess.

^^ good point and, I now recall Kirby said Motul was good lube too. I didn't want to hog their time plus I needed to get on the road. I could have gabbed with those guys for a long time I guess. They seem to stay busy, lots of cars around, there was one guy waiting on an oil change on his '14 sedan and I had to wait when I arrived because Colin (main guy I've been emailing/calling with) was test driving a car. I wish they weren't so far away but, I also hope I don't 'need' them again. know what I mean? lol!

starting to see more complaints about headgaskets on the Forums, but, maybe that's to be expected as the cars are aging and are passing thru the hands of more owners (that may also be getting abused cars or, themselves are not familiar with a coupla quirks about Subaru cooling systems ?) timing chain, no belt to swap still, I think most of us would say the H6es are reliable over-all. Spark plug (DEF use NGK double platinum plugs) and maybe valve cover gasket replacement is a challenge - most other stuff as easy as the H4 to work on. Ours is an awesome 'medium highway cruiser'. I love to drive it. as for quirks, you can check the 'sticky' threads here; http://www.subaruoutback.org/forums/110-gen-2-2000-2004/ (FYI - our 03 H6 OBW has been reliable, but it does have low miles and it has experienced some of the issues mentioned in those threads mentioned above)

? not some residue from a sabotage attempt? what was the stuff you wiped off? just some zinc or 'plating' from the fill pipe or ?