What can I use to seal the exhaust pipe?

You can use Fastix Motores to seal both the exhaust pipe and the manifold (which is the first part of the exhaust pipe and is exposed to higher temperatures).

We do not recommend using Poxilina to repair exhaust pipes or manifolds, as they reach temperatures higher than those the product can withstand. In addition, exhaust vibrations could cause the product to come off once cured.