Engine fumes in cabin

[sbloxxy]

Now that winter is here, I've been using the heater more frequently and I've noticed engine 'smells' inside the car. I read on a previous post that this could well be splits in the orange/red pipes from the heat exchangers to the heater box (?) I haven't grovelled under the car yet but presuming this is the case, where can I buy some of this stuff? I've looked at most of the usual places and can't find anything. On a more worrying note, I also read somewhere that holes in the heat exchangers could show the same symptoms - any thoughts?
Steve

 

[John_Ward]

The source of oily / exhausty fumes in the cabin is one of the irritants of old 911 ownership.
Holes in the exhaust pipes as they run through the heat exchangers can cause this problem, but it would be unusual for the inner exhaust pipes to corrode before the heat exchangers themselves were looking well past their sell by date.
I guess that travelling with one of those battery operated household carbon monoxide detectors might be a worthwhile investment until you know what's going on - they shriek louder and are more practical than a caged canary!