2005 Passat Flex Pipe Issue-Hopefully

Have an issue with a busted flex pipe (or two) that I’m hoping is limited to just that. After returning from a weekend road trip in the frigid northeast a few weeks ago, I noticed that my 2005 Passat car sounded like it had no muffler anymore. Then the CEL game on while driving the next morning. Fearing the worst, I took the car to a local muffler shop and they diagnosed two busted flex pipes-the passenger side is completely busted, and the driver side is nearly there. Simple wear and tear they said (car has 120k miles on it) broke them. The diagnostic of the CEL came back with an exhaust system error (I don’t have the exact code, unfortunately.) Quote of $490 for labor & parts.

Looking for a second opinion, I took the car to a local shop I’ve used for oil changes, etc before and was told that both catalytic converters need to be replaced at a cost of $1995. I was taken underneath the car to look at the damage, and to my untrained eye the flex pipes did look busted. When asked if just the flex pipes can be replaced, I was told yes, but that there’s no guarantee that the cats aren’t bad too. Their quote on the flex pipe fix was $700.

I have driven with these busted flex pipes for 2 weeks now, but would like to get them fixed ASAP. There have been no performance issues with the car-it just runs loudly. Is there any reason to think that the cats need to be replaced? Or is it just the flex pipes as the first shop stated? All help is much appreciated. If I’m not giving enough info I’m happy to provide more.


There is no guarantee that the catalysts aren’t bad too, but there’s no guarantee there is. One of the first things to do when presented with a catalyst efficiency code is to check and correct any exhaust leaks in the system. If there are any, they need to be fixed before anything is else is done.

Go back to the first shop, ask them to replace the flex couplings (at a pretty reasonable price, I might add), clear the fault codes and drive on. If the engine light comes back on, return for further testing.

Do the flex pipes first.

A leaking flex pipe can cause all sorts of codes that relate to exhaust/catalyst efficiency.

And not only causing a loud exhaust.


I would cherck the motor mounts also.

That price for flex pipes seems fair but the chance of needing to replace cats tells me somebody has a boat payment due .

It is almost certain that you only need to have the flex pipes replaced. The reason the check engine light is on is because the downstream oxygen sensor is not seeing the normal exhaust flow due to the leak.
Also, a bad flex pipe will often look good if the braided covering is still intact. What happens is the accordian inner pipe has cracked and that’s the part the provides the seal.

Edit: I also agree with @oldtimer ll that it would be a good idea to check the motor mounts. Excessive movement of the engine can really stress the flex pipes.


Thanks for the info folks. Got the the flex pips fixed at the muffler shop for the quoted price. Mechanic cleared the codes and no CEL since picking up from the shop on 3/6. Just returned from an ~800 mile trip with no issues, performance or otherwise, so hopefully a sign that things are OK.

I did ask for a check of the motor mounts, and that came back OK. Mechanic reported nothing problematic on that front. Again, thanks for assistance all.

Thanks for the feedback. Stay away from that second shop since they know squat about mechanical issues. All they want to do is sell parts like catalytic converters. Tell your friends.