aggravation

1988 S4
My oil fill tube has a single O ring in a groove in the bottom of the tube base that mates with a flat metal surface, no other gasket or mechanism to seal it. It did have some sealant on the O ring and surrounding surface, probably RTV of some type, it was black in color.

I had oil leaking from one of the hoses that attach to the base of the tube but I suspect the O ring seal may have been leaking as well (hard to tell since the broken hose had leaked all over the area).

What is the best way to seal this back up, can the O ring be reused. It looks relatively good, upon close inspection you could see the surface of the O ring had some flat areas where it was smashed down on the metal surface it seals against.
The oil fill tube doesn't look to be deformed.

And on a related note, I gained access to it by removing the water manifold. Can the water manifold O rings be reused and what kind of sealant, if any, should be used there?

UKKid35

The black rectangular oil seal doesn't last long, shouldn't be reused, and doesn't need sealant.

The red roundish coolant seals last longer, shouldn't be reused, and don't need sealant.

aggravation

Thanks, new all the way around it will be.