Re: Oil weights

Posted by TxGoat On 2023/8/23 20:16:17

The zinc additive is designed for certain later model high performance engines with non-roller camshafts. These engines were manufuctured in the late 1950s though about 1972.

Older engines that run at lower speeds with much lower valve train stress have no need for the additive and using it will offer no advantage.

Any good quality multigrade oil will give good results in old Packards.

A 10W30 is excellent for general service in most areas. A 10W40 or 15W40 are good options in hot weather areas, and engines with high mileage can benefit from using 20W50 in hot weather.

I've had good results using full synthetic oil in a Model T Ford that I drive a lot in hot weather at 40+ MPH, which is fast for a T.

I see no reason why it would not give good results in an old Packard.


Packard would have recommended multi-grade oil for pre-war Packards, if it had been available.

I would not run any motor oil in a pre WWII engine for more than 4,000 miles.

I see no need to change modern oil in an old engine that is clean and in good condition at very frequent intervals unless it is driven under extremely adverse conditions.


In this area, non-synthetic motor oil is becoming scarce, and the price difference between synthetic and non-syntheitic has narrowed a lot.

I liked Wal Mart's 20W50 conventional oil for old engines, but it seems to no longer be available in this area.