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Discussion Starter #1
Hi Everyone,

I recently purchased a 745i, 2004. Two problems with it, the first one is it leaks oil (turns out its a stripped oil drain plug, needs a new pan) and there's a check engine light. The mechanic who changed the oil on it told me that the check engine is caused by something related to the catalytic converter, but gave me no further details because he doesn't have the correct scanner tool. So I was wondering...

1- If it turns out the catalytic converters need to be replaced, can I just cut the old one out and get one of those universal catalytic converters welded in place? Not trying to drop $1000+ for OEM cats. From my understanding, the cats and exhaust manifold are one piece, so idk if doing that would be fine or not.

2- I read on a website that the n62 cats are troublesome, and that "it would be better to remove the catalytic converters and to install cat-backs instead." Anyone have any experience doing this on a bmw? Any issues? I don't mind having a loud exhaust at all lol

Finally, is there a DIY to changing the Cats? I'm hoping the CEL is just a bad sensor or related to the oil leakage, since the previous owner got the car safetied and e-tested two weeks ago and it passed.

Appreciate any input,
Thank you
 

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Discussion Starter #3
Thanks for the links. I'm in Ontario Canada, I think emissions here are strict, but not as strict as California. Fingers crossed that the CEL isn't cat related, but if it is then i'll get the cats cut and weld universal ones. Are magnaflow cats any good, or should I go with a regular cat? I just need it to run without a CEL at this point, don't care for performance. Would you happen to know how many hours of labor it takes to drop the engine and take the manifold out? I was thinking of doing it myself, but after some research I discovered that its way out of my skillset lol.

Appreciate your help
 

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Discussion Starter #4
Also I forgot to mention, In one of the threads, member seven11 said he got his welded without even removing the manifold? How would one get access to the cat without lowering the engine and removing the entire manifold?
 

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Also I forgot to mention, In one of the threads, member seven11 said he got his welded without even removing the manifold? How would one get access to the cat without lowering the engine and removing the entire manifold?
See when the last time seven11 posted on this site, and private message him or her.

A good muffler shop should be able to get to it I would believe. From what I understand the magna flow cats are quality units. And you're right getting the manifold off the car is a pain in the butt.
 

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Discussion Starter #6
See when the last time seven11 posted on this site, and private message him or her.

A good muffler shop should be able to get to it I would believe. From what I understand the magna flow cats are quality units. And you're right getting the manifold off the car is a pain in the butt.
thank you, i'm going to visit a shop sometime this week to get it scanned, and if its the cats then definitely will get it done at a muffler shop without removing the manifolds
 

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I went through this last summer was getting error code for passenger side cat tried to use and aftermarket cat from bravarian auto and code came back because I have California emissions so check under your hood to if you do as well if you do only oem cat will work. Oem cat is bout $1200 and but 8hrs of labor the book says cuz they have to move a lot to get it out.
 

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I went through this last summer was getting error code for passenger side cat tried to use and aftermarket cat from bravarian auto and code came back because I have California emissions so check under your hood to if you do as well if you do only oem cat will work. Oem cat is bout $1200 and but 8hrs of labor the book says cuz they have to move a lot to get it out.
So the car is pre-programmed to detect the emissions of your state? What exactly is it that I should I check for under the hood? If it's just an issue with high flow cats, then I'll just get a regular universal cat welded on it. Really not trying to spend $1200 plus $1000+ on labor, especially since it hasn't even been a month since I bought it.
Thanks
 

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Look right under the actual hood for a sticker with emissions info it will tell you there. I knew someone who tried the welding thing and it did not work out. So after installing aftermarket cat and still getting cell light I said was gonna do it right the computers on these cars are real sensitive let me know what does say under your hood
 
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