Removing cats

[tmorgan4]

I'm in the process of taking the two primary cats right off the manifolds out, and can't get to the top two nuts. The R50s are a little different than the Xterras since mine has 6 bolts instead of 3, but should still be the same idea.

Any tips or suggestions?

[Allen Cox]

You have to take the manifolds and cats off as a unit, it's nearly impossible to do it like you're describing. They'll come out through the bottom.

I'm guessing that the manifolds are cracked?

[DamnHippie]

If it is because the manifolds are cracked, I have two good ones here from the 99 qx4 engine I put in my frontier. $25 each and they're yours (includes heat shields that look to be in good shape). That is, if they'll fit -- I notice car-part.com lists some "before 11/98; after 11/98" type options for them.

[Allen Cox]

That's probably because they did update the manifolds on the right side to prevent future cracking. It's a different design with a different heat shield as well. I'm thinking that would be the only difference.

[tmorgan4]

Looks like I might as well check if the manifolds are cracked while I'm dealing with the rest of the exhaust. I'll probably pull them later this week and let you know if I need the ones you have.

Is stud breakage no longer a big issue on the 3.3?

[Allen Cox]

Nope, manifolds. The newer models use the 10mm studs.

[DamnHippie]

Speaking of studs, I think I have a couple of those new too. Nissan wants like $5 each for them, and I bought 6, and then could only re-install 4 (because I had to drill the holes out on the other two). These are the manifold-to-cat studs that're M10 coarse thread on one side and fine thread on the other.

I think I may also have a few of the manifold-to-heads studs because the frontier uses a mix of long and short ones and the pathfinder engine I had used all short ones.