There seems be little consensus on this--Detergent or non detergent straight weight or?
The Model A is driven only in warm weather and around town only. I am currently using a detergent 20-50 ( Castrol GTX)
Would anything else be better?
Does the 20W-50 leak? If not go with it.
I think the text book answer is not: Find out kind of oil they used in 192X - I don't think that would be pretty.
Idealy on paper a straight SAE 30 or 40 non-detergent oil.
My brother runs straight 30 weight in his Model A, but it is a detergent oil.
any motor oil you can buy today is lightyears ahead of what was available when the model A was designed.A lot of people believe and insist that only non-detergent oil is suitable for these old engines. That is pure urban legend. Castrol 20w50 is probably ideal.
I've heard that if you run a detergent oil it is more likely to leak oil and/or burn oil. Isn't that due to the high probability of sludge and old gaskets.
Would it be a good idea to clean things up with Auto-RX, replace worn seals and then run a detergent oil?