Dealer service says I need a new Catalytic Converter front and rear plus misc parts..

[Ghost-Flame]

So I take the X in. to have them read the codes. 2002 3.0 165000 miles.
He says he is getting a catalytic converter code... Immediately he tells me I need new catalytic converters parts and labor over $3000.

Wait why would you jump right to that conclusion? he can't tell me if its the front or the rear, says it could be just a sensor... but his advice would be to replace the whole cat system. of course at that price... for him.

Anyway my indie says a lot of things could be wrong causing that code that are much cheaper and he could do a whole job for less than half the dealer cost.

Do you think I could find a good used Cat System from a junk yard with say under 60,000 miles on the system? And how can I test the cats to make sure they are good?

[bcredliner]

If Indy is worth his salt he will be able to troubleshoot the problem and narrow it down before you purchase anything. It could be an O2 sensor.

You may be able to find a used system but I don't know how you will ever know for sure how many miles on it. Maybe others do but I know of no way to test the cats unless they are installed.

Has you X lost power? Was that the reason to read the codes?

[alecu]

They only way I can think of checking the cats not installed is to hit them and see if you hear a loose rattling sound. That means the honeycomb inside is done. Of course, don't count on this to pick used cats.

[upallnight]

With the cost of the precious metals in the CAT most wrecking yard do not sell the CAT to DIYer. And I believe there is a federal law against the installation of used cat in a car emission system.

[TerminatorX5]

Sun Motors in mechanicsburg?

anyways, just because the code says Cats, it means nothing - it could be that you are running too rich, or too lean, and shit sets off codes down the line... it could be a MAF for all you know... or just a dirty air filter... or, the cats, as the dealer suggested...

tell us more about the reason you took a 10 year old car with over 150K on clock to a dealer - what were you symptoms, if any?

[srmmmm]

Do you run any fuel additives on a regular basis? I stick with Shell gasoline and no other additives and have not had any emmission system issues in 236,000 miles other than a failed secondary air pump.

2002 X5 3.0 236,000 miles
2004 325i 105,000 miles

[Qsilver7]

Most importantly...please share the OBD II DTC code (DTC= diagnostic trouble code)...which is what the purpose of the federal OBD II mandate is all about...it was to bring a "standard" system for all car manufacturers to adher to as far as electronic engine emissions.

You should be able to get a 5 digit DTC code...post that and that will give all of us a direction to look in. As others mentioned, just because you get an 02 sensor code, doesn't necessarily mean that you need to replace your 02 sensors...there could be an issue upstream or downstream of a sensor that is causing it to register a code.

You (or a mechanic) is supposed to use deductive reasoning & diagnostic trouble shooting to determine why the sensor set the fault code. And this is part of the reason why some states like California stopped auto part stores (like Autozone/Pep Boys/etc) from loaning out OBD II readers...customers were reading the codes and throwing money at parts that didn't fix the issue...and since auto part store employees aren't certified mechanics...they stopped this service that most of the 50 states allow.

So if you don't have a code reader, and you don't have any documents that list the code...take your car to Autozone or Advanced Auto, or Pep Boys etc...and read the code (is your SES light still illuminated?).

Again, due to the federal mandate...many OBD II codes are easily figured out because many of them cross vehicle brands. If you have a DTC code, you can google that code to find common symptoms, causes, and solutions.

[bcredliner]

I use Chrevon which contains Techron an engine cleaner. A couple of times a year I add a can of Techron to a full tank of gas. No problems at 108,000 mi.

[Ghost-Flame]

Hey thanks guys for all the replies! I don't have time to read through them all and reply and ruminate on the subject right now. I'm in the labor pit at the moment. I will later.

...Answer to the first question. The car went to the dealer because I wanted them to check the front bushings. Of course they always run a diagnostic. And of course rather than trouble shoot the cat situation, the service thief just hands me an estimate for a complete cat job then he says I ought to go see his sales manager and get a new one. etc etc etc.

I really hate the dealer because he never seems to be on the side of the customer. I asked him why he didn't offer a line of diagnostic that might uncover a cheaper problem first, he just shrugged his shoulders. 9 time out of 10 the customer will take one of those options that are both most profitable for the dealer.

I'll study this closer later and give some answers to the questions... Thanks again for all the help have a beer!

BTW I have not lost any power. the engine purrs like a kitten and runs like a cheatah. I use gas from all different sources... I also use middle grade octane... never had a problem but, I hope I didn't do any damage. I'll get the codes read at auto zone. Gootaa get back to work.

[m5james]

I installed Magnaflow cats in my 740iL and they've worked great, done for $200 installed each. The shop will be able to tell you the part number, it's simply based on piping diameter and HP of the vehicle, nothing crazy since you're stock.

As for using middle grade octane...maybe I'm the only one who thinks it's ironic that you're making a post about needing $3000 of emissions repairs while you're running a lower grade gas than what BMW specifically tells you to put it? Maybe you should change that statement about never had a problem, and you're more than likely get better gas mileage by using what was intended to be used in your vehicle. Will it run on mid-grade, sure. Will the engine run warmer, back off engine timing and get lower gas mileage, in turn maybe being the cause of why your cats are clogged, I'm betting my money on yes.