We bought our westy off the lot in 1984. For 18 years I just changed the oil,filters, fluids, Greased bearings, brakes, ect.  The van was and is the longest running vehicle I ever owned with out a major repair. This is the major reason I Still have it.  At 213,000 miles it  started leaking coolant from the heads. It was a slow leak and it ran great an passed smog but the writeing was on the wall, I replaced it with A Tiico and have been a happy camper. So far about 90,000 on the Tiico.Bill Witz   P.S. It was really my fault because I was trying to nurse the Radiator before replacement. So support System just as Dennis says.