Walker Exhaust Ultra EPA 16467 Direct Fit Catalytic Converter

Installed it, and it went with little fuss.Needed bolts. nuts. and o-ring gasketsFlange at connection to manifold was dead perfect.Flange at rear cat - well- it's damn pain. Why they chose to design this with no studs, I'm not sure. It's a huge time waste.So, get yourself some M10 1.25 bolts with flanges/washers, as you are going to need to tighten these up really well.Good quality CAT for the money. We will see how long they will last!CEL was gone after 300 kms of driving or 5 starts I believe.

It worked but a few things you should know. I replaced both the right and left Catalytic convertors on my 2006 Nissan Frontier just over a week ago. So far the check engine light is off and everything looks good. I saved a ton of money by purchasing these units. However heres why I only rated it 3 stars and a few things you will want to know.First issue: As several other reviewers mentioned the welding on the studs is terrible. They were completely misaligned on both units I purchased. I drilled out the bolt holes on my manifold to 1/2" and managed to force one unit in. However the other unit would not fit even after drilling out the bolt holes. I then attempted to bend the studs but the weld easily broke and the stud fell out. However this was a good thing. With the stud now out I simply used a Hex bolt, nut and washers and didn't have to deal with the misalignment. So my reco is if you have this misalignment issue simply put the thing in a vise and break the weld to get the stud out and then use a M10-1.25x35mm bolt and washers. I used class 10.9 bolts and hardware. That will match what's already there. You will also need a bolt for the 3rd hole as only 2 of the fastening points on this flange have studs. Use the same M10 bolts mentioned above. I'd buy 3 for each unit just in case you decide to remove both of the studs, however removing just the one should allow you to get it together. You will still need to buy bolts for the two studs if you do use them. M10-1.25 class 10.9.Second issue: The flange on the manifold end was fine and I was able to use one 31576 donut gasket and it sealed fine. However the flange on the downstream end has a design flaw in it. Instead of being tapered on the inside to allow space for the gasket to compress it has a large gap left from where the flange is welded to the pipe. The donut gasket nearly completely falls into this void and in no way will create a good seal. I took the advice of another reviewed and used 2 gaskets on this end and it sealed fine. However 2 gaskets is really a bit too thick for the space and the flanges bent slightly as I tightened it down. I was a bit nervous it would break the pipe welds on the flange but it didn't and worked fine. However keep an eye on this as you torque it down. So order an extra 31576 gasket for each unit as you will probably need them. Also there are no supplied bolts for this flange so you will need to purchase a couple bolts. I purchased 7/16" x1.5" bolts, nuts and washers Class 8. I decided not to use M10 bolts here since the bolt holes in the flange that comes on this unit is 1/2" across and are slots. The M10 bolt head will pull right through the hole. However the 7/16" with washers seemed to be just right.Be very careful when you remove the bolts on the manifold heat shields. They come out very easily or break off very easily. Use lots of penetrating oil. I removed 6, (3 on each unit). 5 came out ok but one broke off. Didn't have enough access to drill out the broken bolt so remounted the one shield with only 2 bolts. These bolts are M6-1.0x10mm I believe. (Threw out the box so can't double check). You will need washers as the old bolts have flange heads and the new ones may not.Access to the bolts in this job is horrible. You will definitely need a 3/8" Flex Head ratchet and a 3/8" breaker bar. There were spots where even the 3/8" Flex head ratchet would not fit. My 3/8" breaker bar (12") allowed me to get into a couple really tight spaces.Good luck. Access is the biggest challenge with this job!

My check engine light was on because of the right side converter. I kept getting quotes around $1400 to change the converter and O2 sensors. The Converter, two sensors, and O ring were under $400 on Amazon so I decided to do it myself as there are only 7 bolts you have to remove. It took a lot of elbow grease, but I got it done in three hours. There are some tight spaces and they're annoying, but it's worth it. All you need are 13mm, 14mm, 15mm and 22mm wrenches, liquid wrench spray, a light or two for underneath, safety glasses, a mask (dust/metal particles will fall on you), padded working gloves, a safe way to lift the vehicle, the parts and the nuts and bolts listed below. You DO NOT need an O2 sensor remover. Just use a 22mm wrench.The reason I left 4 stars and not 5. The "Direct Fit" claim is misleading. You'll need to buy machine bolts and nuts. The bolts and nuts I took off wouldn't work with this converter. I had to buy (4) 10x1.25 Machin Bolts and (8) 10X1.25 nuts.

I steered clear of the $80 chinese cats because I wanted a product that would last and have an easy install. The studs in these cats did not appear to have any damage but I could not find any nuts to match them. A trip to Grainger, Lowes, Cincinnati Fasteners, and Fastenal did not find any compatible nuts. They are off just a bit in manufacturing. I finally had to take them to a machine shop and have them properly threaded to M10x1.25 which is the spec. In addition, the studs were pressed in at a slight angle making them difficult to slide in to the receiving holes. For this money wouldn't you think Walker could have included quality nuts which would have told them immediately they are having a quality control issue and secondly to keep the owner from riding all over town to find these fine threaded nuts. Not Happy!

I had read some reviews about how the studs on the upper part didn’t lineup for some people but they were perfectly fine for me. There’s a heat shield that’s in the way of getting to the 3 upper part nuts so I ended up cutting like an inch or two of it and folding it out of the way to be able to acces the nuts. FYI the driver side cat has brake lines in the way which make it harder to reach the topside nuts, thank god for my investment in ratcheting box wrenches! The passenger side is more open & doesn’t have those brake lines in the way. The lower or back end of the converter I bought some metric bolts & nuts to be able to attach to the rest of the exhaust. FYI it definitely helps to loosen or remove the next set of bolts back that are holding the next piece of exhaust on (rear catalytic converter I think it is). This will create some needed space to remove the old catalytic converter and install the new way more easily. I had to do all these same things on the passenger side when I replaced that catalytic converter as well. I believe my computer codes may have been p0430 for this one and p0420 for the passenger side cat. I have like 294,000 miles on my Xterra so they probably definitely needed done by now. Each side took me about 4-5 hours to do, mostly because of either hard to reach nuts/bolts or stubborn rusted bolts that needed cut off and trips to the store to buy new nuts & bolts. Glad these were much cheaper than the ones at auto parts stores and I saved a ton of money doing this myself. I had called a shop and they wanted like $1,000 to do each side parts & labor. So definitely glad I did this all myself and saved all that money, even though it was a pain in the butt!