Cat pipes for Golf IV: Do they exist?

Hi,

I recently came across a link on the forum for catalytic converter repair pipes.

After 10 years, the catalytic converter's inlet pipe has developed holes, specifically right at the end where it connects to the intermediate pipe/muffler with the double clamp. Also, the weld seam on the catalytic converter itself doesn't look great anymore.

One option would be to install a particulate filter, but that might not be the best choice given the short-distance commuting.

"Does anyone know if there are Kat-Reparaturrohre (catalytic converter repair pipes) available for a Golf IV TDI ALH engine? I've only found pipes for the T4 at HJS and Ernst-Hagen so far. Can you simply weld a normal pipe in place? The special repair pipes have a slightly flared connection piece on the catalytic converter."

Yes, they exist. They are called flexible pipes and are available in various sizes.
Simply cut out the old flexible pipe, measure the diameter and length, and weld in a new one.
Well, it's not actually that simple. It's quite a bit of work.
"It's important to cleanly separate the old pipe to have a good base for welding, but it works. And it holds better than the old one. I think mine was 20x5cm."

Hello Tagessuppe,

In my case, the pipe on the other side of the catalytic converter, towards the exhaust pipe, was broken, but the flexible pipe was still okay.
Therefore, I was looking for a pipe (straight, possibly with a small flange) that could be directly welded to the catalytic converter to replace the corroded "outlet pipe." Online, I found suitable catalytic converter repair pipes, for example from Ernst and HJS, which can be directly attached to the catalytic converter, including models that fit the T4. I haven't found anything similar for a Golf.

However, since I would have only expected such a repair to last for about 2 years, I have now decided to go with a DPF (Diesel Particulate Filter). This will involve replacing the entire catalytic converter, including the flexible pipe.

Best regards,

Holger.