Exhaust question

[jremington59]

On my 2000 5.0 there are two cylindrical tubes in the exhaust. I know the one back by the muffler is the cat conv, but what is the one that is close to the exhaust manifold? It's a bulge in the pipe that has a cover over it.

 

[h0und10]

not sure... but.. our trucks have two sets of cats.. so my guess is its the first set of cats

 

[Turdle]

Yes, those are the primary, "functioning" cats. The rear cats are just there for redundancy --in case of primary cat failure.

Passenger side (bank 1) is tucked in tight, driver side(bank2) primary cat is near the bellhousing.

The upstream 02 sensor is almost inside the passenger side ( bank 1) cat, however a good exhaust shop should be able to locate on into a higher flowing cat by torching a hole and welding in a bung.

 

[jremington59]

Thx Jon. I crushed a disc in my back a couple months ago and haven't done any work on either of the explorers. The exhaust was getting louder and I climbed under this morning and there's an awful noise coming out of the one by the bell housing and you can feel the exhaust blowing out. Is it possible to cut the cover off and repair it? It appears more like slots inside than a rot hole. from what I could see. It's all welded and all I can find is the section with both cats for a couple hundred.

 

[jremington59]

Does anyone know why there are slots under the cover in the primary cats?