Interesting. I don't have that hose on either of my M's, open station or cab.Ok my mistake, it’s the passenger side. Lol. Think outside the box. As your sitting in the tractor like a car, left side is driver and right side passenger. But I should have said pump side. Sorry The hose comes right out of the block left of the oil filter and runs to the bottom of radiator. If you look at Messicks under the A42000 WATER PIPE I’m referring to #080(joint,drain). In the picture it looks like it’s straight through but I assure you it’s a plug in the tractor. I’m thinking it’s a drain.