Marvel mystery oil

[macojoe]

My dad was a mechanic for 50 yrs. incl. time in the Navy wwll. he always said the best thing you could do for your car/truck was change the oil and grease it every 3k miles. He didn't like any additives. Said some would loosen crud so it ended up causing problems. On older engines some of that crud takes up slack and prevents bypass etc.
So I never use them, as my vehicles have mostly been older high mileage ones.
recently had a friend

I agree 100%! But I 8always use Mystery oil when I fog the motor, works great