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.

Thanks, guys---I appreciate the responses---Looks like I will try 10-30 oil & 50/50 coolant
The last owner told me he used some type of hydraulic oil in it (hope it hasn't done any damage).

10W30 is a good choice for most localities. I don't know why anyone would put hydraulic oil of any type in an automobile engine, including a Model T. That said, I doubt if it did any damage. Most hydraulic oils are light bodied, temperature stable oil with anti-foam additives and good lubricity and film strength. But motor oil designed for gasoline engines is best for a Model T with a stock or near-stock engine. Any good 10W30 motor oil will meet, and far exceed, all Ford's motor oil specifications for the Model T. Conventional oil, synthetic blend, or full synthetic oils all work well. If you run your car in cold weather, a 5W20 or 5W30 is a good choice. Thick oil is not needed and NOT RECOMMENDED for use in Model Ts for a number of very good reasons. Multigrade detergent oils offer many advantages, and there is no good reason not to use it.

Jim: you made the right choices. You’re going to find over time here at the Forum that there are people out there that just HAVE to experiment on their T’s. They try the damndest things and swear on a stack of bibles and Grandpa’s grave that it works. Use what you’d use in your modern and you can’t go wrong.

Charlie B in N.J. wrote: ↑

Sat Oct 04, 2025 12:05 pm

Jim: you made the right choices. You’re going to find over time here at the Forum that there are people out there that just HAVE to experiment on their T’s. They try the damndest things and swear on a stack of bibles and Grandpa’s grave that it works. Use what you’d use in your modern and you can’t go wrong.

Agreed. More important than the particular grade of oil, just make sure you always have enough in the engine. Check it with every fuel-up, at least until you get accustomed to its normal oil use.

Wally ST 5w-30 or 10w-30 oil works fine for me.

Oil Wet-n-slick. Coolant 50/50 Distilled H20 and Green stuff. bobt

No matter what oil you choose, your T engine will use and mostly leak a lot of the oil so it is important to remember to regularly check the oil level (before each drive is a good habit to get into). Never let it get below the lower oil cock.

Have fun

The oil system is gravity fed and splash, so it is not under any pressure. The lighter weight oils will actually give better lubrication.
Norm

And if you have to room, store a couple quarts of oil somewhere in the car and an empty bottle that u can use to add water to the radiator, even if it is just an old coke bottle.

I liked the old style steel quart oil cans... but the liquor bottle style plastic quarts are easier to store in a car. All gas stations used to have air and water for free.... and most had motor oil out front in a rack. But most no longer have water or air, and convenience store oil is often high priced.