what oil to use?

[mickey350]

I can't wait until my service manual arrives in the mail. Until then, what kind of oil and how much for a C-175 engine?

 

[rustyfarmall]

Any brand of good quality engine will work. 10w-30, 10w-40, 15w-40. I would not use 5w-30. Not real sure on the capacity, but a minimum of 6 quarts. Some of the info you need is available at external_link

 

[Dan Bear Kelley]

Tricky question in some ways. One thing to be wary about: if the previous owners were not running detergent oil, then you can cause all kinds of oil leaks by switching to detergent oil. That having been said, I really appreciate detergent oil. You will too, the next time you do a tear-down. Even so, be careful! I saw it once, where a guy put some extra oil additives (detergents) in an old engine (a Mopar slant six). All the gunk and hardened carbon from the engine went right into the oil pan and blocked the oil pump pickup. We pulled the pan, cleaned it all out, but the thing still threw a rod shortly afterward. (I bought the carcass, and threw a newer slant six into it. Ran great!) Lesson: When in doubt, use non-detergent oil.

You don't want to get too heavy an oil in one of these old engines. 30 weight should be fine. You're not doing a tractor pull (are you?). These are not high compression, high RPM engines. Don't bother with multi-viscosity oil. You're going to be running your tractor in a very narrow range of temperatures. It won't hurt, but it is more expensive.

Hope this helps! I appreciate the chance to help someone else on this site, as so many here have helped me greatly over the years!!