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Discussion Starter · #1 ·
So after Merced VW failed to perform any action on my vehicle . . . good ole Bill Cooke Imports in Ithaca, NY is replacing both cats under warranty. The past history of the vehicle was that it started throwing under-efficiency codes on both cats at around 38500. Codes came up multiple times and I brought it into Merced VW for diagnosis.

Each time they told me that it was because i hadn't driven my car for a few days. Well the first day I get my car into Ithaca, it pops up another CEL. I made an appointment with Bill Cooke for today at 830. I get a call at 915 and they're going to replace the cats under warranty (overnighted parts and should have it by the end of the day tomorrow).

Now 40k seems to be a very short while for these cats to go . . . what causes this?

I change spark plugs every 10k, use Mobil 1 5w30 or 0w40 (no overfill), run it on 93 or 91 octane and run some chevron fuel system cleaner through it every oil change. I don't think I stress my vehicle any more than most people do yet my cats are clogged after such a short period.

Dave
 

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Several problems will dump extra fuel into the engine. A bad O2 sensor,temp sensor or coil packs will cause the problem.
 

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Maybe they overfilled your oil? It's a common problem. VW dealers have been known to dump as much as 1+ quarts more than the car is supposed to take. That could poison the cats.

There should be an obvious problem that would cause this.

Before you blow the cash you might want to have someone log the O2 sensor voltages and analyze the pattern to see if the cats are really shot. Do a search on oxygen sensor and cat, I posted some links on how to analyze O2 sensor logs about a week ago. I don't have the links on me now.
 

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Discussion Starter · #4 ·
Not blowing any cash . . . . warranty :)

The car would have been long sold if i needed to replace the cats with my own $$$.

As for oil over fill . . . it was overfilled a little during the free maintenance for the first 20k . . . but i believe that stopped after i started giving them Mobil 1 to put in at around 10k. Now i guess i just have to worry about them welding everything together correctly. . . .

Bad
Dave
 

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Dave,

Just curious...did your coil packs go bad on your car? There was some speculation at the height of the coil pack problem that following VW's advice of driving the car to the dealer could result in premature cat failure later.
 

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I have had two coilpack failures in the past, and recently it was detected that my O2 sensors are bad. Fortunately that CAT is not bad... yet. After warming it, it was still Ok.
I'll be replacing the O2 sensors on monday.
 

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Discussion Starter · #7 ·
Altair 4 said:
Dave,

Just curious...did your coil packs go bad on your car? There was some speculation at the height of the coil pack problem that following VW's advice of driving the car to the dealer could result in premature cat failure later.
I have a V6 so no coilpacks. I did have a few misfires however from one bad spark plug back at around 25k, but that was taken care of quite quickly and it never came back again.

I should be picking up the car later today so i'll see what kind of job they did on the cats . . . .

Dave
 

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Discussion Starter · #8 ·
UPDATE: Got the car back. VERY noticable difference in acceleration. Exhaust tone is louder. Feels like my dad's new GLX.

Each of the VW cats were $1923 x2. They also replaced all hardware and gaskets. Then VW was billed for 9 hours of shop time because they had to remove the entire exhaust & etc. (two techs worked on it).

Well i'm happy i guess . . . . good thing i still had the emissions warranty.

Dave
 
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