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Discussion Starter #1
Hi everyone,
I just purchased a 2004 745i two weeks ago. So far I love it except for the fact that it started leaking oil right when I got it, and gave me a check engine light. I took it for an oil change yesterday and they told me that the oil drain plug is stripped, which is most likely why its leaking. As for the check engine light, apparently they say its an emissions code related to the catalytic converter, but they didn't give me any further details because they don't have a BMW scanner. Until I can get the car to the dealer (closest appointment is on the 23rd but will try to find an independent shop), I'm expecting the worst and doing some research on catalytic converters. Even though the previous owner got the car E-tested and safetied and it passed.

So my questions are:
1) Since the OEM cats are so expensive (I'm a student, can't afford to shell out $1000+ per cat), can I just get one of those universal catalytic converters installed? From my understanding, the cats on BMWs are right next to the headers, so maybe I can get them cut off and weld the universal one somewhere under the car along the exhaust?

2) I was reading this website ( and they said that I should remove the catalytic converter and install a cat-back system instead, but it didn't make any sense since the car-back connects the back of the cat, right?:rofl: Or are they correct?

Appreciate any input,
Thank you_a__a2_
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