Water pump bearing froze. Belt melted on road to
GoeffreyH is not correct. On this engine the water pump is run by a small, single, separate belt which cannot be adjusted by the alternator because it (and the water pump itself) are on the opposite end of the engine from the crank pulley and other accessories, such as alternator, A/C, etc. which are driven by the main serpentine belt. The water pump is driven by a pulley on the end of one camshaft. Your confusion stems from the change from the old system, in which a longer belt was used with a tensioner in the traditional fashion, and the new system on 2004 vans where the tensioner was eliminated and a 'stretch fit' belt was used. Stretch fit belts have a springy component (like a rubber band) and keep their own tension this way by being stretched a bit to fit over the pulleys then holding snug against them. The problem is that some parts books erroneously call for the old belt for vans which need the new one. So the first belt your mechanic got was longer (to fit over the extra tensioner pulley) and static (not stretchy). On these newer vans, you can still see the mounting boss where the tensioner would have gone, it's part of the castings so it's still there. That's why it looks like there's a place for a tensioner but like none was ever there. Both your observations are correct. The only thing you need to do now is make sure your new belt is the right one, that it's a stretch fit belt, so it maintains tension (otherwise the water pump pulley will eventually start to slip and spin too slowly and the van will overheat) and also that it's not TOO tight, which will put you out of another water pump. The correct belt, if it's from NAPA, would be 030250SF.
Jul 11, 2010 |
2004 Mazda MPV