forester2002s

Generally speaking, the crush-washers can be re-used several times. If the plug shows no sign of leakage, I wouldn't worry about it.

Could be some debris in the heater-fan. Perhaps a dried leaf hitting the vanes of the fan-cage?

Here are some measurements that I made on the old rings that I recently replaced (I tend to hoard old parts, just in case...): - These are for a 2002 Forester - Subaru O-ring #73039TA020 cross-section dia. 2.2mm; ID 11.0mm - Subaru O-ring #73039TA040 cross-section dia. 2.2mm; ID 16.8mm These are probably accurate to about +/- 0.1mm. A used a digital-caliper, but it's not easy getting a stable reading on the soft rubber O-rings.

Front wheel-bearings deteriorating?

I wonder why a 2016 is for sale? EDIT: It's actually a 2015, so 2-years old, not 1-year old as I had originally misread.

Fuel-filter partially blocked?

Isn't there a rubber-covered plunger-type switch that is depressed when the door closes? If that switch got stuck, the warning light would stay on.

Yes, a C-clamp makes it easy to compress the piston. I use an old brake-pad (reversed) between the 'mushroom' end of the clamp and the piston face.

A oil+filter change sometimes works wonders. Also worth checking the spark-plugs. Could be 'pinging' from one cylinder. Any CELs? (1995? Not OBD yet?)

Some Subaru warning lamps can be replaced with Radio Shack (US) mini-bulb #272-1092. Cost a couple of dollars each. The company that took over Radio Shack in Canada, 'The Source', used to also carry these bulbs, but they've gone upmarket and no longer sell small components like bulbs and switches - too bad! I'm not sure which model years use these mini-bulbs, but my 2002 Forester uses them. It's a lot of work to get the combination-display out, but it gives you access to all of the mini-bulbs.

Sounds like an electrical issue. First things first: - check that the battery is good. Voltage across the battery posts should readabout 12.5V with engine off, and about 14V with engine running. - check that the battery terminal-clamps are tight and not corroded.

Check the oil level first. Take out the (top) plug; oil level should be up to the bottom of the hole. You can put in your small finger to feel inside the diff if the level is slightly below the hole. Use a turkey-basting squeeze-tool to add more oil. Jack up both rear wheels (parking brake off). You won't be able to 'spin' the wheels, but you should be able to turn each wheel by hand. The other wheel will turn in the opposite direction. There should be no noise or grinding from the rear-diff.

Take photos! If the engine is currently running well, then make marks on the old belt and on the timing notches (use a wax pencil, or child's crayola stick - yellow works well). Then take photos of that setup BEFORE removing the old belt. So when installing the new belt, you can refer to the old photo to check tooth-count etc. Only takes a minute.

Wheel bearings? Sometimes causes a 'rumbling' sound, plus steering-wheel shimmy if it's the front bearings.

Or get a used OEM axle from a junk-yard, and reboot it. I'll probably last longer than any aftermarket copy.

The 2017 Forester has both an "Low Oil Pressure Light", as well as a "Low Oil Level Light". I don't know when Subaru first started including the Oil Level Light. It would be interesting to know if this coincided with the use of low viscosity oil.

By 2010, the separator-plate (behind the flywheel) was no longer made of plastic. And in any case, a broken separator-plate would leak copious amounts of oil. So IMHO that's not the plastic that you are seeing.

Year & model?

I've also had this problem on my EJ251. I always leave the car to cool overnight before checking the oil. Then withdraw and wipe, then reinsert the dipstick. Then withdraw again, and read both sides. The lower reading is the one to use. As the years have gone by on this engine, I check the oil more frequently. At least every 1000km, or every 500km if the level is going down. My engine is the original from 2002, now with a replacement turbo head-gasket. No oil leaks, but it needs about 1-Litre every 3000km.

My 2002 Forester is similar. When I pull and release the hood-lever, nothing appears to happen. But if I then lift the edge of the hood with my fingers, it then pops up. It's been like that for a few years. I'm used to it now.

I love Wikipedia, and I am an occasional contributor. But beware of those compression figures for the EJ16, since there's no knowing where they come from. Wikipedia entries are supposed to be backed-up by references, so that one can trace the info back to the source. In this case there are no links to any credible sources. Those numbers may be correct, but I would add some skepticism to the mix.

Can you describe the vent in more detail? Or post a photo?

+1 Grounding is what came to my mind, as I read the symptoms.

If nothing else works, how about some tape over the two 'eyes'?

Shocks: Apart from smoothing out road-bumps, shocks will also smooth-out vibrations from out-of-balance tires. That constant (and speed-related) vibration can wear out the internals of a shock, causing the distress that you have experienced.