I noticed a puddle of coolant forming on the passenger side of my truck below the pssgr door. I can't tell where it's coming from other than this general description (it's manifesting aft of the front pssgr tire). I took it to a shop and had the system pressure tested and the mechanic told me no leaks. He added coolant and everything was groovy for a couple more days. Then it happened like crazy. Last time I drove it, there seemed to be a serious coolant leak happening in the same spot.

Any thoughts on where this might be coming from?

 

Rear heater coolant line?

 

that's it - thanks