Use the motor oil that offers the best protection!

We all want to protect the engines in our classic cars.   When the Spring Fever hits you and you want to get your old Caddy out on the road, remember to change the oil first!  If like me, your Caddy has not seen much use over the winter.  Modern motor oil contains less of the additives that fight friction, like zinc and phosphorus, which acts as an anti-wear agents.  Oil for newer cars made from 2001 to present have the code SJ on the API seal.  These contain less additives for emission reasons.

 

When you’re shopping for oil for your next oil change, look at the API (American Petroleum Institute) symbol on the bottle.  The round symbol is divided into three sections:

 

 

The upper arch identifies the oil’s performance level, using the letters “S” or “C”, followed by another letter.  S = service and C = Commercial.

The middle section identifies the oil viscosity.

The lower arch identifies the oil’s fuel economy rating.

 

I want to focus on the top arch designation.  The Commercial (“C”) grade oil is intended for diesel powered heavy duty trucks (fleet vehicles), but are perfectly fine for gasoline engines, like in our old Caddy’s.  Many “racing” motor oils also have this designation.  These “C” grade motor oils have more additives, so they’re what I’m going to use next time I change the oil in my classic car.  Here are some of the motor oils that have higher zinc content.

 

ANTI-WEAR ADDITIVES SPECTROGRAPHIC ANALYSIS:
	Zinc (ppm)	Phosphorus (ppm)
AMSOIL Series 2000 Synthetic 0W-30	1599	1288
Phillips 66 Trop Artic 10W-30	922	784
Quaker State 10W-30 4X4 Synthetic Blend	1078	856
Havoline Formula 3 20W-50	1085	834
Valvoline Racing 20W-50	1192	1077