MTFCA Forum

I am a new 1917 T owner and want to know what the best choices are for engine oil and coolent

My preferences.
Valvoline racing 30 wt. Any good detergent 30 wt will do.
Water soluble oil for the radiator in distilled water. Sold @ auto parts stores as "anti rust & water pump lube."

Buckle up. Many opinions coming.

Ford recommended what amounts to 20W, but what did they know about Model Ts?

10w 30 oil and 50/50 conventional coolant.

speedytinc wrote: ↑

Wed Oct 01, 2025 11:22 am

My preferences.
Valvoline racing 30 wt. Any good detergent 30 wt will do.
Water soluble oil for the radiator in distilled water. Sold @ auto parts stores as "anti rust & water pump lube."

Buckle up. Many opinions coming.

This^^^^^^^

As stated: 10W 30 oil and 50/50 coolant. Don’t bother with non detergent 30W. Gets too heavy in winter. Experience talking here.

Save your money and go to Wal Mart, Auto Zone, Oriellys and buy their store brand 10w30, or 10w20 HD oil. It’s much better than oil Ford ever put in Model T’s.

John kuehn wrote: ↑

Wed Oct 01, 2025 3:07 pm

Save your money and go to Wal Mart, Auto Zone, Oriellys and buy their store brand 10w30, or 10w20 HD oil. It’s much better than oil Ford ever put in Model T’s.

John, Menards (we pronounce it "MAYnerds ha ha) actually has Rotella 10w30 usually for LESS than the "off brands" at auto stores. You can't beat the quality of Rotella. And if you're concerned about zinc and phosphorous it's still got the highest levels "allowed".

But whatever detergent oil that is on sale, it will be better than what was available a 100 years ago.

10w40 here, but then its a hotter engine with an oil pump where I'm not dependent on the Ford splash system. In the past coolant has just been water as it leaked out so fast there was no point in antifreeze. With the new radiator (something needed for the past 40 years) and rebuilt water pump I can now run 50/50

How much of an effect does the different weight of oil have on the transmission function? Any?

Viscosity affects clutch function. Heavy (cold) oil will cause the car to creep in neutral.

Model Ts are designed to use what Ford called "light cylinder oil", which is about 20W. Ford recommended a quality "Light" oil for general use, and recommended a light oil mixed with 10% kerosene in cold weather. The lubrication system will not function as it is supposed to with thick oil, and neither will the clutch and bands. Thick oil might also contribute to problems with triple gear bushings, and it will make starting more difficult. Thick oil will interfere with roller timer function, especially in colder weather.
For a stock or near-stock T engine, a good 10W30 is an excellent choice. In cold weather areas, 5W30 or 5W20 is a good choice. There is no good reason to put thick oil in a Model T, and a number of good reasons not to.

I like Valvoline oils. I use 15-40, 10-40, 10-30. They all work fine here in Southern California.