Have a diesel smell in the cab when a/c is on, but I turn on the a/c reculation button it goes away. Climbed all over and under truck and no visible leaks.

Cool but confused.

Items replaced :
Heads and studs a year ago
EGR delete same time
Oil cooler. Two weeks ago

 

SO its got a Upipe Leak (Or Exhaust Leak) or a Fuel filter cap thats cracked or Loose

Also look at the front the upper Fuel filter where the blue spring goes a couple leaked there

 

diesel as in raw fuel or are you talking exhaust smell? Mine had that smell after an egr delete. Aparently the up pipe had a crack in the accordian looking joint.

 

Good point. I had a similar situation... I couldn't see a leak but could smell diesel fuel. Once the leak got worse from the pressure spring housing, I could finally see the fuel dripping. Look really good around the housing with the engine running.

 

Thanks,
Found small leak in by the fuel filter and going to ck exhaust gaskets.