My friend had a 2016 legacy with the 2.5 boxer engine. It has 150k highway miles and burns some oil. It currently takes 5w20. Is there any oil I can switch to that will help it stop burning.
No.
How much oil is it using? How old is the PCV valve?
It is burning about 2 quarts every 5k miles which is when he changes the oil
It is burning about 2 quarts every 5k miles which is when he changes the oil
Hopefully he is not actually letting it get two quarts low before adding oil!
So it is using a quart every 2500 miles. Most manufacturers consider oil consumption up to a quart per 1000 miles to be "normal". (That's malarky, but for warranty purposes that's what they do.)
Check the PCV valve, and check for any oil drips. If it's not the PCV valve and it's not leaking oil then it must be burning in the engine. (If that much oil was getting into the cooling system you'd know it!) Do the spark plugs and tail pipe show signs of oil? To check condition of piston rings you'd need to do a wet versus dry compression test.
He has been adding the the oil as it burns. Thanks for the tips I will check it out.