I have a '95 SRW Dodge Cummins Regular cab truck and it has suddenly developed a strong #2 diesel smell inside the cab. I can't figure it out. I don't see any leaks under the truck, either when it's running or stopped, and I don't smell diesel when I raise the hood, or when I stick my nose into the bed where my aux. tank is located. I can't think of any fuel lines that run through the cab--it wouldn't make any sense to route them that way, and I certainly didn't run any there when I installed the aux. tank.

It's worse when the heater/AC fan is directed to "recirculate" with no outside air coming in. I can't figure out why it is suddenly smelling like #2 diesel. Anybody got any ideas?

 

Check the rubber cowl seal that runs along the firewall area and seals the AC intake against the back of the hood.
When mine falls down I get a diesel smell too.

 

Thanks Shovelhead. My seal has fallen down before, with no smell, but I'll check it and see. Maybe that's it.

 

Found the problem. The seal was nice and tight--that wasn't it... but that plastic bottle of STP Diesel Anti-Gel that I forgot about in the cab since last winter had started to leak!! Ha!