Wayne wrote in last week describing what can only be described as a scary situation (I know, it’s happened to me.) It seems the water pump on his nearly 30-year-old Universal diesel finally had a bearing failure. What happens when this occurs is that the impeller inside the pump housing begins to scrape on the inside of the pump housing and, depending upon the design clearances, maybe even the front of your engine block.
Wayne wrote in because he probably remembers that I’ve talked about what I describe as “black fairy dust” all over the front of your engine being caused by alternator pulley alignment due to missing shims on the alternator mount. The fairy dust is actually the fan belt(s) on your engine slowly grinding away due to the misalignment situation. It’s powered rubber. Well, Wayne wanted to remind me that this observation may not always be caused by alternator misalignment. Wayne’s right, it could also be water pump pulley misalignment. The bottom line here is that this sort of failure can really spoil an otherwise great cruise if it happens when you are far from home. Don’t count on finding a new water pump quickly or easily, and no it will not be inexpensive!
So, what pulley am I talking about here? Check out the photo below. The red arrow is pointing to the pulley to check:
You really should grab this pulley and see if it rocks from side to side at all, checking for any radial run-out in the bearing. You may also want to remove the belt temporarily and give the pulley a few spins so you can feel for any roughness in the bearing(s). Better to find these things out while you are making ready than underway. If you do feel roughness, or there is a lot of radial run-out of the pulley, you should order up a new water pump ASAP. That way you’ll be ready when it does fail. If you are already seeing the fairy dust, get some new belts too because they are effectively worn out if they have already begun spewing rubber dust all over the front of your engine. Oh, and don’t try to cheap out here; trust me, it is not cost effective to try and rebuild these pumps.