Greeting,

I am sealing up a few oil leaks, one of them being the oil cooler return hose at the sump. When I took off the oil cooler hose at the sump I noticed there was no thread sealer or O-ring. The end of the hose where it connects to he sump fitting is flared. Is there supposed to be an oil ring in the sump fitting, it looks like there is one but its just old oil film and should I use some type of thread sealer. When I took off the fitting on the sump I did see an oil ring on that fitting where it attached to the sump and I have been made aware that the fitting needs to be centered when reinstalling.

 

I think I found my answer on thread sealer and O-ring. a

• The seal happens at the seat, this is a fared connection, not the threads
• Sealer on threads = more problems than solutions

 

It looks like the arrow is pointing to an O-ring, I see this on some Chrysler transmission cooler lines using inverted flare connections. It shouldn't be needed if the metal to metal seal is doing it's job but Chrysler has added the O-ring and new ones come in their gasket kits.