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Hi all,
Does anyone know if there is a decoder for the catalytic converter reference numbers?
This is my issue:
I had my cats' honeycomb removed because I was getting a lot of white smoke and smell of rotten eggs out of my exhaust.
Now the car stinks of gasoline, just terrible.
So I'm looking or some replacement cats, OEM.
The reference numbers stamped on the cats is not what is indicated as a part number from any and every JLR parts site.
Example not necessarily correct, just to show the format of the numbering.
Stamped: FW93-5E212-AB
Part number: C2Z30790
Can anyone give me a link to a decoder?
I have a 2013 Jaguar XF 3.0 SC RWD and I'm thinking its safe to assume that the XF (X250 and X260), XE (X760) and XJ (X351) all with the same configuration as mine, should have the same cats, but no, the parts sites show a different number for each vehicle, there's about 30 different iterations of the cats, rediculous.
Some help please understanding the cross referencing of these cats and if I can buy cats from another version for mine.
Before you add new cats, fix the problem on engine.
The exess smell comes from unburned fuel. White smoke can indicate an burning coolant what might be the reason for incorrect burning. Do you lose coolant?
You will destroy your nes cats quite fast if the issue is not fixed. (unburned fuel burns inside of cats)
One or more fuel injectors might be stuck open.
Up to you but when I researched this for my 2014 XJR after destroying the driver's side cat from a bad injector I found just the opposite?
All 3.0L and 5.0L engines use the same converters and the same basic exhaust system. This surprised me as I have the top of the line XJR with the factory 550HP engine. I just assumed (Bad I know!) that Jaguar used different converters and exhaust systems. Even the pipes and mufflers are the same or nearly so. Note I "think" the AWD versions are different. Add the XK to your list as those use the same drive trains. Do note I only looked at the first gen XF which yours is. The later Aluminum XF may or may not be the same. I don't know.
This appears to be part of the reason Jaguar used that strange V-6 block with the 2 extra holes in it to match the V-8. Now all the accessories on the front of the engine are the same and all the stuff from the transmission to the back of the car is the same. The differences will be in the tail pipe lengths at the back of the car if the wheel base is different as my XJ came in SWB or LWB. There is also some WB differences between the XF,XJ,XE,XK.
This saved Jaguar a tremendous amount of money as they reduced the number of parts variations.
I purchased a used 3.0L XF drivers side cat and it fit and was identical to the factory unit in every way I could measure. It's been 3K+ miles and I have went thru an emissions test with zero problems or any difference from my OEM cat. Power and fuel mileage are the same too. I have a tune and a pulley so I know what the car can do.
I have never been able to make any sense of the markings on Jaguar parts as they compare to the actual part number. They maybe are Engineering numbers of some kind but I don't know that there is a list relating the two numbers? Sure would be handy!
Post back if you do find some other differences. I am sure I could have missed something!
Another tip (and I live in the rust free South!) is plan on replacing the nuts and studs at the engine side of the cat. Maybe yours will come right off but mine were rusted solid and after a lot of work I got one stud off (with damage) and finagled the cat assembly out of the car where I could get my oxy acetylene torch on the rusted stud. Took about 30 minutes and red hot metal before I got the tiniest movement of the stud. Just kept working it back and forth a little at a time. Eventually I got it moving and backed it out.
If your good with a torch or take it to an exhaust shop I am sure they could do it place in minutes. I tried and was afraid of all that heat around VERY expensive Jaguar parts!! Could not get it hot enough to do any good. I have a lift but the lack of working room limited what I could do with it in the car.
If you want to get the stud and nut ahead of time here are part numbers I used. This should be a common part but there are a number of different stud lengths and threads. So I got them from Jaguar. This is a cut and paste from my previous thread.
Vasara just a note about the white smoke? I also thought white smoke only came from coolant but when these injectors fail you simply will not believe the amount of thick pure white smoke that pours out of the exhaust pipes! I have been working on cars for a few decades and have never seen that. When I finally got my car to start after several weeks of failures it took almost 20 minutes before the car stopped blowing white smoke. I could not see across my shop it was so thick! These DI injectors must flow a heck of a lot of fuel to produce that smoke. No wonder it ruins the cats!
I was so happy I got it started I ran and got my wife to celebrate! Even she mentioned the incredible amount of white smoke!
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Last edited by clubairth1; Jul 25, 2025 at 08:43 AM.
I did see that the shape and support of the left side pipe from an AWD is different and will not be a direct fit.
All the others seem to be the same, but what got me was the difference in numbers.
I'm glad you had the experience of installing one from an XF because I found a pair from a X351 V8 in really good shape and for a good price, from Poland, so I'll probably go with those.
The studs holding the exhaust to the manifold were replaced recently when they removed the honeycomb from the cats and I also live in a country where rust from harsh cold and rainy weather is not a concern (Portugal).
I had problems with my injectors too. All the three on the right side had to be replaced and two coils and I had the timing kit replaced also, all 6 sparkplugs, plus engine supports both sides, new coolant deposit, (no loss of coolant) just the level indicator stopped working and was always showing low level.
I'm ordering those cats now before someone else does.
all chassis have different downpipes, you might get some to fit but they’re still different. this will get you a basic understanding of ford engineering numbers