i have an 2001 a4 1.8t and recently have been having a couple of issues. I noticed that there is always white smoke coming out of the exhaust, i have engine codes that say my secondary air pump is having issues. but the main issue is whenever i turn on the heater the entire cab smells like exhaust. what are the possible causes? any help would be appriciated.

 

Clogged cats. Will cause the sai code and the exhaust smell. Not sure if it will cause white smoke.

 

i have always heard that clogged cats would result in a sulfur smell. is that not always the case? and how would clogged cats force exhaust into the cab only when the heater is going? thanx for the quick response!

 

It's not that the exhaust is only leaking when the heater is on, but the inlet for the heater is right about where the exhaust leak would be. So everytime you have the heat on, it's sucking in the leaking exhaust.

Could also be a leak at/near your combi valve. That would cause the SAI code and a pretty large exhaust leak.

 

your white smoke problem can be cause by a bad turbo, bad valve stem seals. the exhaust smell is most likely from clogged cats. and clogged cats will also cause the sai code and the exhaust smell.

 

Anyone else for clogged cats?