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Correct engine oil for my 1960

Started by cadillacman, October 23, 2011, 01:15:26 PM

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cadillacman

Hi, what is the correct grade of oil for my 1960 Cadillac I've had a look on the forum and i'm confused.
I've always used 20/50 living in the UK (classic car oil) over here,
What do you all use

thanks in advance  :)
Chrome is my favorite color!

Dave Shepherd

If the engine is not worn I use 10/30 with some zddp additive, 20/50 maybe in warmer weather, or in a worn engine.

Mike Josephic CLC #3877

This subject has been discussed at length, most recently about 6 weeks
ago and many times previously.

You may wish to put "oil recommendation, engine oils, etc) in the "search"
function to see more info than you'll ever need.

My recommendation:  Use any major API approved brand of 10W30 oil, which
is what this engine was designed for.

Additives are not needed unless you intend to drive it at high mileage
(few thousand miles per month) or pull a trailer (not likely with our cars).

Mike
1955 Cadillac Eldorado
1973 Cadillac Eldorado
1995 Cadillac Seville
2004 Escalade
1997 GMC Suburban 4X4, 454 engine, 3/4 ton
custom built by Santa Fe in Evansville, IN
2011 Buick Lucerne CX
-------------------------------------
CLCMRC Museum Benefactor #38
Past: VP International Affiliates, Museum Board Director, President / Director Pittsburgh Region

Roger Zimmermann

If you have no problem with that 20/50 oil, you have no reason to change...In one of my cars I have 10W40, in another one 15W50 and, honestly, I don't care too much. Remember that those engine have a rather low specific power and that the oil used in 1960 was of marginal quality compared to the good actual products.
1956 Sedan de Ville (sold)
1956 Eldorado Biarritz
1957 Eldorado Brougham (sold)
1972 Coupe de Ville
2011 DTS
CLCMRC benefactor #101

Chris Conklin

Just curious; I've heard people mention using certain oil weights in certain weather conditions. I have always thought that the oil was specific to the engine's tolerances. What does weather have to do with it?
Chris Conklin

dadscad

The engine manufacturer recommends a specific oil viscosity for the tolerances the engine is built to. If you use an oil that is too heavy for the tolerances built into the engine, you will/can starve critical areas of the engine of lubrication and create excessive wear. If you use an oil that is too thin, same thing, the viscosity film will not be sufficient to protect against metal to metal contact and will create excessive wear. 0-30, 5-30, 10-30 motor oils are all 30 weight oil at operating temperature. The difference, the flowability at start up. The 0-30 will reach critical areas much faster than a 10-30 will. They both will protect equally at operating temperature, the 0-30 will protect better on cold start ups over the 10-30.

A straight weight oil is rated at it's viscosity at operating temperature. At temperatures lower than operating temperature, the oil will be thicker and will resist flowing easily. That is why multiviscosity oils are recommended, they flow easily at low temperature, start up, and still protect the engine at operating temperature. A 10/30 multiviscosity oil flows as a 10 weight when cold and protects like a 30 weight when hot. The oil manufacturer uses a base oil of 10 weight and adds polymers to increase viscosity when the oil heats up. Polymers are like coiled springs that shrink when cold and expand when hot. They are not really a lubricant, they just thicken the oil to give  protection at operating temperature. These polymers do sheer and wear out, that is one reason it is important to change a conventional motor oil at regular intervals. The oil will sheer out of grade over time and you will loose the protection of operating temperature viscosity. Today's oils are vastly superior to the lubricants available when our cars were built, but, viscosity is still the same deal. If your car manual recommended a 10-30 oil I would not use a heavier grade unless the engine was just worn out and tired. I would use one of the multiviscosity 30 weight oils in a sound engine. In my 63, I use a 5-30 full synthetic oil.

HTH,
David
Enjoy The Ride,
David Thomas CLC #14765
1963 Coupe deVille