I had a talk with my mechanic and i have added mystery oil to try to insure i am not having a stuck ring in the car. I did a rubber glove test for pcv function. That is why we are trying the additive.

The oil i used and have used is castro’s high mileage. First 400 miles zero oil use then it used half a quart in 150 miles. No smoke cold and on reg interstate seems good.

I’m open to that but how do you tell?

I have 740 b230 f. Engine died and replaced it. First 400 miles everything ok. Then i changed oil and suddenly it starts using oil. Going down long grade oil smoke rolls out back. I thought it was pcv issue. Replaced flash back device and cleaned box. No difference and still using oil. I live in mou...