1941 Chrysler Windsor- Oil Type?

[41WindsorHighlander]

I just acquired a 41 Chrysler Windsor Highlander with Fluid Drive/ Vacamatic- It is a 6 cylinder. What type of oil should I put in with a complete oil and filter change? 10W40? the original Workshop manual does not specify, but discusses the outside temperatures and how it effects the oil. Your experienced opinions would be appreciated! Thanks, Rob 

[Den41Buick]

There will be a lot of discussion on types of oil you should use. The first question is, has the engine been rebuilt at some point recently? If the answer is no, then I would recommend a non detergent 30W. If it has been recently rebuilt then you can look to something more current like a 10W30.

[TTR]

51 minutes ago, Den41Buick said:

The first question is, has the engine been rebuilt at some point recently? If the answer is no, then I would recommend a non detergent 30W. If it has been recently rebuilt then you can look to something more current like a 10W30.

This ^^ is a reasonably good start, but some consideration should be given to climate for and type of intended driving.

Might also be worth to invest into owners manual, as it might have factory recommendations for oil viscosities.

Edited July 5, 2022 by TTR (see edit history)

[Rusty_OToole]

10W40 is as good as anything. Multigrade and detergent oils have been around since 1951, if your car has had an oil change since then it probably got 10W30 which was the default choice at garages from the fifties thru the eighties. Look for oil change stickers on the driver's door jamb for confirmation.

 

Do not use good ol' non detergent 30 weight. You don't need it and it won't lubricate your motor properly especially when cold.

 

Fluid drive unit and transmission are filled separately. They take either 10 motor oil, or TDH tractor fluid  ISO32 grade. You can get it at Walmart, farm stores, and auto parts stores. TDH stands for transmission, differential and hydraulic fluid. Fluid drive needs to be checked and topped up every 10,000 miles or so, transmission oil should be changed every 10,000.

 

You might toss a little Marvel Mystery Oil, Bardahl, 2 stroke oil or Redex in with the gas. Today's gas is very dry and a little oil will make your valves and rings last a lot longer, and prevent the valves from sticking. This is not mandatory but a good idea.

 

Later... slightly newer hydraulic shift M6 transmissions take 10 oil or TDH fluid. I am not sure about the 1941 vacuum shift models. They may use something else.

Edited July 7, 2022 by Rusty_OToole (see edit history)

[Larry Schramm]

Don't forget that any oil today is better than the oil that was available at the time the vehicle was built.

 

As long as you get a viscosity of oil appropriate for your driving, any oil will do.

[The 55er]

Just for the record, I have a bunch of these old Technical Service Bulletins from the period and they show what the factory would have recommended back in 1941. However I would agree with Rusty's advice above. 10W40 is as good as anything, I have been using 10W30 in all my old cars for many, many years. 

[EmTee]

I spoke to the elderly owner of a 1917 Model T last week at a cruise-in event.  I was asking him about driving the car with that unique 3-pedal system that Ford used at the time.  He went on to tell me about someone who had just asked about what engine oil it used.  He said that he told the person who asked the question that he goes to Walmart, scans all of the oils on the shelves and picks the cheapest one!  I replied - sure, even that oil (whatever it happens to be) is 100x better than the best oil available when the car was new...