francesconyc

Today I noticed some smoke in the engine compartment that I've never seen before, but let me describe exactly all the facts that precede it:

• today I replaced the fuel filter + fuel accumulator together (some hiccups but I have no leaks (I have fixed them) and the car starts great afterwards.
• to replace those parts I removed the big plastic hose (Hot Air Duct Blower 93021103100) to have more room
• I never started the engine or stared for minutes at my engine, especially without that hose removed
• I started the car and it was running great, waited to check for fuel leaks, 1 minute or 2 or. maybe more?
• at some point, I noticed some smoke coming out of the heat blower housing (but the blower was off so that was not the culprit) (see pic1)
• I'm not sure of the color or the smell, I didn't feel a specific smell maybe plastic? but it didn't seem to be a burnt smell. it actually seemed like the regular smoke you get from the back of a car...the car exhaust fumes maybe?
• the smoke started after a few minutes of idling, not right away, which I guess that's why I never noticed considering that I rarely or never idle unless I'm stuck in traffic.
• last note: my heater flappers are stuck in the CLOSE position (air directed on the ground), I never experienced heat in the cabin, nor I can know if the smoke could actually enter the cabin (say in case the heat exchanger is cracked internally and they mix fresh air with air more engine

ideas:
- the smoke could be from my sausage/exhaust silencer (I parked by mistake on top of my cheap car cover, which burned and stuck underneath, creating a dark burnt layer (see blurry pic2)
- I read it could be oil dripping on the exhaust, a typical problem, but I also know the PO replaced all the gaskets on the engine covers (not sure how recent)

what else could it be? smoke from the heat exchangers...going backward to the heating ducts?
Honestly I'm still not clear on how the heating system and heat exchanger works ...





pics attached