Hey guys, I'm new as it gets and still learning engines but I have a serious problem to address. My Comanche is feeding grey-ish smoke into the cab through the floor heat box whether the heat is on or not that smells like burning oil. I have researched this online but no one is experiencing it quite like this. I have no clue what to do here so any help from you guys is greatly appreciated.
There's almost no possible way oil can get in the heater box to smell like burnt oil; I doubt it's oil. BUT, the blower motor and/or resistor can be going bad and causing this burning smell. In the MJ years the resistor is usually the issue, but it may be worth replacing both while you're at it. If you don't (best case) the blower motor will stop, or (worst case) you could have an interior fire caused from the resistance of the heating/shorting out of the wires.
Here's a YouTube video of a resistor placement of what looks like a right-hand drive diesel XJ:
I'm sorry, I didn't word that very well. The smoke is fumes coming from the engine, not oil in the heat box. Somehow the fumes and smoke are coming through the vents. It has nothing to do with running the heat or anything. I'm still going to look into what you said though. I really appreciate you giving me something to consider.
Could be an exhaust leak.
Mine had an cracked exhaust manifold and I got lots of fumes when it was hot and running hard. I also had a couple of dried out loose grommets in the firewall. Replaced (welded) manifold, replaced donut gasket. Fixed grommets. All good now
1990 XJ Laredo - White & Chrome
1988 MJ Pioneer - Metallic Green and Black