Re: what kind of oil do I use in a 1951 Packard 300

Posted by Rusty O\'Toole On 2009/5/10 10:16:34

A couple of thoughts-

10W30, multigrade, detergent oils were just coming on the market when your car was built. Chances are, all it has ever had was 10W30 during its working life because that was the "default choice" of all dealerships and garages for most of the last 50 to 60 years.

In recent years oil companies have cut down the anti wear additives especially zinc. This is OK for late model overhead cam engines but not so good for older pushrod engines. The lack of antiwear additives can cause rapid cam and lifter wear in pushrod engines because of the weight of the valve mechanism.

Your flathead engine has a light weight valve train like an OHC engine so the ordinary oil should be fine. If you are at all concerned, diesel rated oil still has the full additive package. The diesel oil you usually find at your local stores and gas stations is 15W40.