If the car is a quart and a half low does Subaru have a shut-off feature to keep from hurting the engine.

Low engine oil level will shut off Fuel pump if more than 1 quart low.....Bad oil pressure sending unit controls Fuel Pump relay also........If more than 4 Years old, it would not hurt to replace it..........

the smell could be oil leaking on to the exhaust from the rocker covers.(common problem in Subaru because of the side mounted pistons. Engine stop oil leak might fix other wise will have to get tappet cover seals replaced as they crack over time from the heat) easy enough fix. a tell tale sign is signs of engine oil stains or signs of oil dripping on to the exhaust(can locate by looking under the front of the car at the bottom of the engine itself) and this is probably the cause of the engine knock due to low oil.it will continue to leak till the problem is fixed

It will not hurt the car engine if there is no oil in it as long as it is not started with no oil in it. In most cases the engine can run about 1-2 quarts low and still be ok but that is not recommended. The engine should never be run with the engine oil light on or oil pressure gage extemely low.

No it won't

If it has the 4 cylinder in it 5W20 and if you have the 6 cylinder it could be either 5W20 or 10w30. I usually use 5W20 in cold months and 10W30 in hot months. As far as capacity goes, as a general rule if you change the oil but not the filter, not something I recommend, then you start with 4 quarts and adjust from there (Basically by 5 quarts). If you change the oil and filter then start with 4 and a half quarts and check the level and adjust as needed. You could use up to 5 quarts maybe a little more. Make sure you check the level before starting then start the vehicle for 5 minutes shut it down then check the level again after 5 minutes. Make sure the level is between the marks.

Not at all......I've been a technician for approx. 15 years and always add the last half quart and have never had a problem.

It certainly won't hurt. Also, check the timing.

I had the same issue a few years ago, but with a Subaru Forester. The Subaru service department suggested starting the engine and shutting it back down six to eight times. Let it rest half a minute of so between starts.

I hope this helps, and please do let me know.

Spoem

Worn valves.

Probably didn't hurt it, my 2002 was ran for 2000 miles 1 1/2 quarts low on oil due to dummies putting only 5 quarts of oil back in it after changing the oil. It takes 6 1/2 quarts. It didn't hurt it at all.