Water pump differences

lazytv · Post by **lazytv** » Sat Nov 28, 2015 10:21 am

Bought a water pump but it varies from the old one. The new one has a longer shaft and the four threaded holes don't line up with my fan clutch. Do I have the wrong water pump? Wrong fan clutch or do I have to swap the water pump fan clutch flange.

CabbageFumes · Post by **CabbageFumes** » Sat Nov 28, 2015 11:47 am

Sounds like you got a later water pump. If your original fan clutch is still good, get an early pump. If your clutch is tired, get a new later pulley and fan w/clutch. The early style clutch is crazy expensive if you can even find one.

Mike W. · Post by **Mike W.** » Sun Nov 29, 2015 1:52 pm

Yep, that threaded hub is for the later style pump which was used in most 80+ M30s. No idea why they changed the pulley from a square bolt pattern to diamond shaped, but they did so they aren't interchangeable. I do still have a stash of used early style fan clutches for a reasonable price if anyone's interested, but agreed, new ones are stupid expensive.

lazytv · Post by **lazytv** » Mon Nov 30, 2015 9:30 am

Wow what a difference a weekend makes..

The earlier style water pumps are still available you'll just need to search for a BMW from 1978 or earlier.

I found one and installed it on. Problem solved. Thanks for all your help.