Smoke from the dashboard vent - help

[carbon14]

After my engine heating up (slow traffic, red lights...) almost too much, some thick gray smoke came out of the dashboard vent on the side of the heater matrix (my car is lhd, so for me the passenger side) and smelling pretty awful, like burnt plastic... not a pleasant moment...
A check in the engine bay showed nothing abnormal (thanks God, nothing burning). I found nothing visible also when looking upside down in the car at the vent ducting (I mean what is visible...)...
Anybody experienced this already / some hints available on what it could be ?
Thanks in advance,
C14 - Griff500 1994

[V8 GRF]

There's a possibility it might have been sucked in from the car in front if you where in a queue if there's nothing obvious?

[carbon14]

Thanks for the idea, but no, as the smell also happened afterwards when driving and standing with no car in front of me...

[Barkychoc]

One of the motors gone up in smoke for the heater valve / flaps?
Sorry I don't know the exact configuration but I know there are small motors in there.

[Loubaruch]

As Barkychoc said quite likely to be one of the heater actuating motors. Try to adjust each heater control and check that you can hear a motor whirring for each one. If one is silent could be your problem. If you can identify the culprit report back and no doubt someone will be able to steer you into the problem area.

[Barreti]

Carefully check to be sure the heatshield is still intact on the inner wing passenger side.

It might be your engine mounts are shot which allows the engine to twist more and the manifold rubs the heatshield away.
Then your manifolds cook the fibreglass behind it and it smells like your wiring is on fire.

[lazyitus]

This happened to mine about 6 years ago on the M6. st myself and pulled into the services pretty sharpish. Never found out what it was and never had an issue since.

TVR's - gotta love 'em.

[carbon14]

I think I found the culprit.. a 1 inch plastic cover that had been placed where the air conditioning hose was entering the bodyshell (aircon has been removed by the previous owner) - not far from the wiper motor, above the exhaust manifold - has disappeared. I guess it fell and burnt on the exhaust manifold, the smoke went into the 1 inch hole just above (about 3-4 inches distant), and went via the heater matrix ? to the vents into the car... sounds a bit science fiction to me though...
Thanks to all of you,
C14

[carbon14]

Well, I was bitterly wrong in my last assumption about where the smell and light smoke was coming from...
The smoke came from a short in the fuse box, which caused a fire during my last drive yesterday in exceptionally hot and sunny day for this season.
Luckily I could pull out quickly, took off the panel in front of the battery (the strong smell was coming from there), pulled out the battery, the ECU etc. and extinguished the flames with a piece of cloth I had grabbed from the trunk.
A 1 minute action. 200 heart beats trust me. Car saved.
Don't want to scare you, but hell I thought this is how a car goes away...
Cheers,
C14

[Aussie John]

Bloody lucky! and well done in putting it out.