forester2002s

You say that the old battery had a "20A drain"; and the new battery has "less than 1A drain". How was this 'drain' measured? I ask, because if the 'drain' was a leakage current via the wiring harness and through the car, then that points to a problem on the car itself, and not necessarily a bad battery. The difference before and after might be because of the intermittent nature of your original starting problem. A large leakage drain, such as the 20A you mention, could be the alternator diodes failing, for instance. If however, the 'drain' is a leakage internal to the battery, then I don't know how this is measured. Other than to disconnect the battery, and to monitor the battery voltage across the terminals. Did the store say how they measured the 'drain' on the battery?

+1 On 'older' cars, the oil-warning lamp is activated by an oil-pressure switch, and means that the oil-pressure has dropped below a safe value. When that light comes on (it sometimes flickers first, before going full on), it means that the engine is NOW being starved of oil. Unless the engine is turned off immediately, damage will result. If it keeps running, the engine is toast. On later cars, there may be actual oil-level sensor, in which case the warning lamp may just be a warning to add oil. But I wouldn't recommend driving any car with an oil light on.

Mono vs. stereo? A mono-plug has two 3.5mm 'cylinders'. A stereo-plug has three. Hence the number of wires. EDIT: Or, a stereo-plug might appear to have only two wires, with the third-wire (ground) being a shielded-wire. Depending on how the cable was stripped, the shielding might have been cut away at the end, leaving only the two (left & right) wires visible.

FYI: My 'Canadian' 2002 Forester came from the factory with NO block-heater.

All those warning lamps come on at start-up deliberately. It's so that you can see that all of the lamps are working, and are not burnt out. Your Owner's Manual (available online) should show you which lamps are being tested. If any of the lamps don't work during this brief test, they should be replaced.

Noise gets worse when you brake? It's not the brakes themselves, is it? Something loose? Flapping around? Just a long shot...

My 2002 Forester came equipped with a cabin-air filter-box. But the box was empty, with no filter-media installed. The box is under the glove-compartment, and has two removable rubber 'doors' on the bottom, each held closed by a couple of metal clips.

I wonder if the water could be getting into the car from above, instead of from underneath. It's not unknown for rainwater to leak into the car through the rear door-seal, or through the mounting -holes for the roof-rack. Water can drip down hidden from view behind the roof-liner, and find it's way down into the spare-tire well. Just a thought...

You could start by flushing & bleeding the clutch hydraulics. That might fix it.

This PDF file is from the Factory Service Manual for a 2002 Forester, so should be similar to yours. Piece (A) of the Belt-cover is the one to remove to expose the timing-belt; it is held in place with 3 screws (10mm hex-heads). Piece B should be left in place; in any case, you cannot remove it without taking the lower crank-pulley off. Good luck. Edit: That file says to first remove the v-belts and the crankshaft-pulley. But you don't need to do that just to remove the (A) cover. ME45 Belt Cover.pdf

+1 on what MTom said. Inspect the belt. All you have to do is remove the left-side belt-cover. Just 3 screws will do it. If there is any cracking of the belt, it will show up as transverse cracks on the back (smooth side) of the belt, particularly as it bends over the exposed cam-shaft pulley. 30 minutes maximum.

How long since the fuel filter has been changed?

I've had that same P0420 code twice on my 2002 Forester. I just clear it, and it goes away.

Your link does not work. There's a problematic C: in the link, which leads nowhere.

Could be grease leaking out of a split rubber boot on the passenger-side inner front CV-Joint. The burnt grease smells something like fried grasshoppers.

Many 'weird' electrical problems are due to bad grounding problems. I would check all grounds associated with the headlights, and cruise-control.

I would replace the engine-mounts and the stabilizer-links first, and then see if this corrects the problem.

If you can get underneath the car safely, check the various components of the suspension, both front and rear. Grab hold of the various rods and links, and give them a good shake. You can expect some movement, but you should not hear any rattling. And check all of the suspension rubber bushings visually. Sometimes the rubber deteriorates, and it is pretty obvious to see when these need replacing. One particular component to check is the rear stabilizer-link. There's one on each side, kind of 'C' shaped, with bushings at each end of the 'C'. If the bushings deteriorate, they will rattle when you shake the link. And this can be another source of 'rumbling'.

Try your local 'Industrial Fasteners' wholesale counter. More and more places now carry metric bolts.

Also, the front crankshaft oil-seal sometimes leaks. Easy to replace when doing the timing-belt.

Replace Engine oil + filter; Check transmission oil level; Check rear-diff oil level.

One possibility: Did the clutch release bearing (I'm assuming that you installed a new one) slide freely on the input-shaft for the transmission? If not, then the release-bearing might get caught-up on the shaft, and not allow a smooth clutch operation.

Does your car have a parking-light switch on top of the steering column? You may have accidentally turned it on.

From the underside of the head, you'll need to turn the spark-plug clockwise to get it out. An easy-out may not work, as it will only grip in the counter-clockwise direction.

If it's leaking at the bottom of the timing-belt cover, then it's most likely coming from the front-crankshaft seal.