I have a 2000 Chevy Blazer ZR-2. I recently had to change the rad out. When I took out the radiator noticed what looked like oil in the very bottom metal lineto the radon the drivers side. But there was no oil in any other of the lines. Why is this? I've kept a close eye on it and theres no antifreeze on my dipstick at all, my coolant in my rad and reservoir isn't murky, as if there was oil in it. Ever since the rad change my blazer has been running great. If anyone could help me with this I'd greatly appreciate it.

 

How do you know it was oil? It was probably just dexcool sludging, or corrosion of the line by the dexcool.

 

not sure which line your talking about, howver the rad has both a tranny and oil cooler in it. Drivers side is engine oil cooler, and passengers side is tranny cooler lines. Could it be teh oil cooler lines you were looking at?

 

yea my truck runs a oil cooler through the radiator. if they r hard line then it is most likely an oil cooler.

 

Yep, just the internal engine oil cooler.