Hi everyone,

I get strong "hot" smells through my heater. It smells like an engine that is at running temp (you know, kind of oily), and the smell starts very soon after starting the engine (about 30 seconds). Is it likely to be a problem inside the heat exchangers?

TIA

You have a Kombi dont you?

It will be either (i think) oil that has leaked from a valve cover on to the heater box - this will apply for either T1 or T2
or
If a T2 isnt there a heater box gasket on the exhaust? that can sometines leak.

Does ot backfire at all?

If not and definetiley oily smell - check for a leaking rocker cover

Yeah it's a kombi (doh I should have mentioned that). It doesn't back fire at all, it runs quite well. I guess I need to look for oil leaks. I know there are lots, I just have to decide which ones I can ignore and which ones are important. :-S

Smelly hot air in a VW is always a problem with a lot of things contributing. Especially on a Kombi. The air for the heater is sucked from the engine bay, so any oil/dirt/fuel in there gets sucked through by the fan, so give it a good clean and check for any leaks, especially the engine to body seal! (Always a good idea). Secondly as Blue74L said any oil leaking from pushrod tubes or tappet cover goes straight onto the heat exchangers, so if the oil gets inside the exchangers it too will pollute the heated air. Lastly if all the pipes are old or even original there is many years of dirt and grim built up inside of them which again gets smelly as it heats up.
All that done, I have my system all pretty clean and well sealed, but it’s still a little smelly. I don’t mind it (acquired taste!!!) as I know there’s no oil or exhaust fumes in there, but new passengers often complain.

Give the engine undersides a good degrease and hose-down - a hoist is best for this but otherwise get in and under with the hose as best you can. Then a few days later it's easier to see where any oil leaks are coming from.

VW heaters always have some degree of enginey smell about them, even when the heater boxes are new or freshly painted. Even if there are no leaks at all, the air still comes from the inside of the engine bay. Leaking or rusty heater boxes might be a source of carbon monoxide, which can be dangerous. A workshop can test that for you. Otherwise, you learn to live with the smell, it's part of the joys of owning an air-cooled Volkswagen.