SL/R129: How to tell if the cats are blocked/shot?
MBWorld Fanatic!
Joined: Mar 2003
Posts: 3,445
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From: WOT somewhere in the Bay Area
1951 Caterpiller D6
Mine sounded like they had rocks in them. Not very rhythmic at idle but increases with RPM. Almost sounds like a lifter or rod knock but it is not exactly in synch with RPM. Very inconsistent.
I never really checked mileage or performance but if it suffered, I didn't notice.
I never really checked mileage or performance but if it suffered, I didn't notice.
MBWorld Fanatic!
Joined: Mar 2003
Posts: 3,445
Likes: 3
From: WOT somewhere in the Bay Area
1951 Caterpiller D6
Originally Posted by MeJay
I think you can smell it if your cat has gone bad. It usually smells like rotten egg.
Not true. Rotten egg smell means that it is working but under some abnormal conditions. The smell is sulfur in the fuel that is being converted to hydrogen sulfide. Under very lean situations, sulfur will build up in the cats and will get burned off when the engine starts running richer.
Sometimes, different batches of fuel have higher sulfer amounts and can lead to increased "rotten egg" smell.
Greg
