odd smell from heater/AC

[TjMiller]

Looking for some direction here with a issue ive been having with a smell in the cab. Noticed it earlier this year when first started using the AC in the summer. It is NOT a musty old sock smell it is more of an oily chemical smell, not burnt oil. At first I thought it may be a refrigerant leak but AC worked all summer so figured it wouldve drained the system by now. When I checked the condensate drain tube I noticed the fluid coming out was kind of milky. I thought maybe heater core has a slight leak but not sure if where the core is located it will drain into the box or the floor board. Im not familiar with this dash yet so I didnt want to start taking it apart and have it down for a couple days. Any thoughts?