leaking valve stem seals will cause....

[supraman7mgte]

hey all,been awhile since ive been here
so basic question
I had some bad valve stem seals awhile back,gave the good ol James Bond smoke screen
got them replaced but now I'm wondering what effect(affect) that it might have had on my exhaust system.
could this damage and clog my cat?
before I go out and throw money around i'd like to get some info on this first
thanks

 

[jetjock]

Depends on how long and how bad but generally speaking oil will damage a converter by coating the substrate and preventing the exhaust stream from coming into contact with the wash coat containing the actual catalyst. That can result in anything from a mild loss of converter efficiency to complete poisoning.