1999 NB Rattling....again!

[naviathan]

Ok I bought my car around April last year. About 3 months later the catalytic converter started rattling. Under the car I could hit it with my hand and hear the honeycomb rattle around. I took it to a shop and had it replaced for ~$200. 3 months later she's rattling again and it sound like the same rattle. I haven't crawled under her yet, but I will later today since I have to replace my rear calipers, rotors and pads thanks to a frozen caliper.

Anyhow, no CEL is popping up for anything. What the heck could be causing her to eat up cats?

[n7plus1]

1. The OEM cat sucks. (at least for the 2.0l) Why VW decided to make the header/dp/cat 1 piece blows my mind as well..leading me to number 2

2. Aftermarket cats usually suck even worse. Im not surprised that lasted as long as it did. cutting pipe and replacing it shouldnt be the way to replace a cat...thanks VW

[Smileybug]

I cat on my car was 11 years old before it finally failed. Aftermarket cat lasted a year and a half with no problems whatsoever. Still looked new after my accident. Aftermarket is completely fine. No reason it should have crapped out after 3 months.

Have you scanned the car for codes anyway? May not throw a CEL but there still could be codes. Maybe a failing O2 sensor or something.

[naviathan]

Originally Posted by Smileybug

I cat on my car was 11 years old before it finally failed. Aftermarket cat lasted a year and a half with no problems whatsoever. Still looked new after my accident. Aftermarket is completely fine. No reason it should have crapped out after 3 months.

Have you scanned the car for codes anyway? May not throw a CEL but there still could be codes. Maybe a failing O2 sensor or something.

I have scanned it anyway hoping there might be something off, but I've got nothing. A friend of mine said that the pre-cat O2 could be reading off, but not enough to throw a code, but if it's not enough to throw a code could it really be enough to destroy two cats?

[Smileybug]

You need to scan it with VAG-COM. That way you can also take a peak at your O2 sensor performance to see if they are working as expected. I never had any issues with my pre-cat sensor so I can't tell you if it would eat up cats without throwing a code, but I did have the rear one fail. I did get a code though, showing it being "intermittent" and then a CEL when it finally crapped out entirely.

Ultimately you need to get under the car though and see whats up. Could just be a lose heat shield or something.

[naviathan]

Originally Posted by Smileybug

You need to scan it with VAG-COM. That way you can also take a peak at your O2 sensor performance to see if they are working as expected. I never had any issues with my pre-cat sensor so I can't tell you if it would eat up cats without throwing a code, but I did have the rear one fail. I did get a code though, showing it being "intermittent" and then a CEL when it finally crapped out entirely.

Ultimately you need to get under the car though and see whats up. Could just be a lose heat shield or something.

There's one person in this area with a VAG-COM and he's difficult to get in touch with. I haven't gotten under the car yet today, but I'm almost done with the brakes. Have to go back to Auto Zone for another caliper. The one they gave me had a stripped bleeder valve.

[Smileybug]

You have a decent amount of dubbers in your area. I think I may have directed you there before (you may be a member, not sure), but check out ncdubs.org if I haven't. Post up in the regional section and see if anyone has a VAG-COM. I'm sure a few people do.

[naviathan]

Originally Posted by Smileybug

You have a decent amount of dubbers in your area. I think I may have directed you there before (you may be a member, not sure), but check out ncdubs.org if I haven't. Post up in the regional section and see if anyone has a VAG-COM. I'm sure a few people do.

Ok, I used the locator for VAG-COM and only found one person, but I'll check up on the board. This car is starting to cost me more than I paid for it at this point.

[n7plus1]

Originally Posted by Smileybug

I cat on my car was 11 years old before it finally failed. Aftermarket cat lasted a year and a half with no problems whatsoever. Still looked new after my accident. Aftermarket is completely fine. No reason it should have crapped out after 3 months.

after reading your post and from what ive read in the past, your experience seems to be the exception.

[IndyTom]

Originally Posted by n7plus1

after reading your post and from what ive read in the past, your experience seems to be the exception.

I hate to differ. My 2000 Beetle has the original cat and 167k miles on the clock. No issues whatsoever

If the Cat burns out then there is an issue somewhere else. If you don't correct this issue than replacing the cat is pointless since whatever is causing the cat to fail prematurely will just do it again and again.

[naviathan]

Well I finally had an opportunity over the weekend to crawl under the car. Turns out the aftermarket cat had heat shields on it. The upper shield had 2 of 4 tack welds holding it in place and the lower shield was hanging on by one. Ripped the heat shields off and she's quiet again. Thank God it wasn't another cat.

[Smileybug]

The early 2.0L cats were sort of junky. They extended the warranty on them to 10 years/120k because of them being failure prone (the innards would just disintegrate) and mine failed exactly how they said it would. But never had any issues with other cats. I believe the cat on my GTI is original at 117k. And really, it failing on my NB wasn't that big of a shock. The replacement took less than 30 minutes and held up fine. I've not seen anyone on here complain that their aftermarket unit failed and I'm sure there are a number of people with them.

Remember, those with problems are going to be more vocal than those without. I doubt the aftermarket units are that bad.