67elco

I just bought this truck yesterday: I didn't notice this problem during the test drive/inspection. I drove it back home about 2 1/2 hours from the dealer I bought it from, running the a/c the entire time (which worked perfectly fine), and today I noticed a small amount of oily water (definitely not coolant) on the passenger front mat: Which appears to be coming from up above: My day job is running a GM Certified Collision Center, and I have access to GM SI, and I was able to pull this diagram: I had read from others that its common for the drain to clog and the water then fills up the drain tube and overflows into the cabin. I pulled the driver's fender liner back and was able to snake a small plastic bristle brush up the drain about 4-5". Nothing came out and the the brush was bone dry. I'm not sure if I still have warranty coverage as I'm right at the 3 year mark. I could not find any definitive answers via search as to what is the source of this problem.