oil indicator level cap gasket

[locomotive2111]

After much research on this subject to improve tightness of cap and improving pcv system I discovered the original gasket on the cap was leather backed by a brass piece like spring. I placed another thin gasket between the brass and leather to make up for the worn leather thickness . This worked great. A Felpro 5019 bowl gasket could be used in a pinch if the leather is lost or damaged but could be slightly sanded to decrease its thickness.  Unlike the leather the cork gasket would not wear as well where you constantly check your oil level.  Some small aircraft use a similar system and use silicone gaskets like part # 08-13773 at Aircraftspruce.com to seal the dipstick tube. For your info the gasket is 2 1/4 o.d. and 1 i.d.1/2

[Rus Curtis]

Interesting.  I'd never considered there might be a spring backed seal in some of these engines. 


I just kept adding layers where the gasket used to be until I got a tight seal. 

If this isn't stuck up inside the cap, is it possible to post images?