I have an exhaust leak and it is the flange just downstream of the cats. While I have this off, I would like to replace the studs and bolts in the flanges, Does anyone know the length and pitch of the studs that I need? I will have both the front and rear flanges apart, so I will do both of them.

Has anyone done this already? It does not look like it will be that bad to do as long as I dont twist off any of the rusted bolts.

2010 S model

Thanks

 

I got into this repair yesterday. In case someone else does this, the bolts in the flanges are M10x1.5 x 25mm (doorman #981-525).
When I was taking out these bolts, I noticed the catalytic converter was very loose. After I got the flange unbolted, the cat would have just fell off.
The upper flange (where it bolts to the exhaust manifold) had a defective weld. See picture below.
This is a factory converter.

I would think that since this came from the factory like this, there are many, many more cars with this issue. This is a dangerous situation because of exhaust fumes (carbon monoxide) getting into the cabin and could actually cause someone to die! If you smell exhaust fumes or think you hear an exhaust leak, get it checked out.

This repared cost me about $30 in gaskets and bolts. Took about 9hrs to do this because of the difficulty to get to all the bolts and breaking them loose. Had to heat most of them with a torch.

If you look at the welds, there is 0% penetration into the flange. It was a nice looking bead, just no peneteration. I repaired this by re-welding the flange back on.

 

I have seen this on Frontiers before.

 

There should be a factory recall on this because someone could die from CO. poisoning.

This is an expensive repair if you have to take it to a shop.

 

Agreed, about $1100 all in at Meinike (includes cat)