maxa4trubo

I bought new Long Engine Block Part Number: 06H100036C for Audi A4 B8 today, it will take few days to get delivered in meantime I called few shops around to get estimate for engine swap and one of the mechanic told me that he recommends to replace Catalytic Converter, and I'm like I never heard anyone did that I read a lot about B8 2.0T engine consumptions issues and replacements that follows but not on single case I heard to replace the cat. I called another shop and asked about that they told me if there is no issue with cat right there is no reason to replace new cat cost over $2K OEM version.

SMac770

Pretty much what the second said; why would you replace it unless you specifically have some issue with it.

maxa4trubo

He's argument was since your engine is burning oil the catalytic converter may be clogged up that can damage new engine due to higher pressure, there is no fault codes the only issue with engine is oil consumption

SMac770

If you think the cat has an issue, test it. Simple enough to confirm backpressure or airflow through the cat, or check if the interior material has become loose, etc. But you don't just blind swap it for no good reason.