I was just poking around underthe hood of my 1986 420SEL and noticed a broken hose coupling. There is a three or four inch long hose (about 3/4 inch diameter) that comes out from the passenger side of the engine block. It is located between the oil filter housing and water pump/ alternator (I'm not sure - looks like that kind of thing) The hose goes to what looks like a thermostat (at least it is about that shape and size) I am not down any fluids, and I have run the engine and looked to see if anything was coming out. Is this some kind of exhaust gas release hose? Can anyone enlighten me? It looks like the metal coupling that attaches this hose to the engine block has rusted in hald and that is why it has come off. Expensive to replace/fix?