My uncle has a 2001 4.0 4x4 ranger and it has a coolant leak that we are having a hard time finding. It is on the passenger side of the truck. The block appeared to be wet on the passenger side towards the front of the engine at first. I thought it was the heater control valve, but told him to take it to the ford place to have them verify it. They confirmed what I had originally thought, so we replaced the valve. He drove the truck the next day and after he parked it we had coolant puddling on the passenger side again. This time, the block was dry, and after looking over the engine bay, I noticed a slight drip under the coolant recovery tank. So, I took the hose off, cut the damaged end, then put it back on securely with a hose clamp. He took the truck out again, drove it and let it sit over night. Checked the next day and it is still leaking on the passenger side. This time, coolant was draining between the inner/mudflap area. Both hoses that are connected to the heater core are bone dry, and I pulled the carpet back inside the truck on the passenger side to verify the core wasn't leaking inside the truck. It was dry. Were could it possibly be leaking? I think we've eliminated almost everything on the passenger side of the engine bay that could leak.