Originally Posted by
ZERACER
I know in the old days we would mix 30 weight and 20 weight if that were all that was available. These days with the multi grade synthetics would any harm be done if you mixed a quart of 5 w 40 with seven quarts of 0 w 40 or vice versa. Can this harm or effect the viscosity and lubrication of the oil to the point of doing damage?
When I saw the question I guessed the wrong name of the person who was asking it. LOL
No problem I would guess as long as both oils were for the same or similar original uses and both were good and clean.
When the average driver gets his oil topped up these days when some is used up, who is to say what viscosity was in there to start?
We are not average drivers we know what we use, well most of us anyway.🙂