The International Cessna 170 Association

What does the "DET" mean on my oil cap?

http://i1352.photobucket.com/albums/q64 ... b4sbe.jpeg

Det ? ? ? ? " Detergeant " maybe ???

I can remember that when detergeant oils first came on the market it was not recommended to install them in high time engines inasmuch as they might shake loose too much accumulated stuff and cause the start of high oil consumption.

I don't think that the one that has "DET" on it is an original style 170 cap. All I have seen (not very many, I admit) have "ears" like the one in the bottom of the photo. In any case, the painted "DET" is an aftermarket application, and should have no bearing on what should go in the crankcase. I don't think there is any "detergent" oil approved in our engines (ashless dispersant is NOT detergent).