240D water pump question
 

Per records from po, a new water pump was installed approx 10k miles ago. In pic below, there is a hole approx 3/16" dia on the top of the housing and I can see the shiny shaft spinning thru the hole. Should it be open and exposed to the element like that? Shouldn't it have some type of a plug or seal?

http://i31.photobucket.com/albums/c3...072907_007.jpg

Holes in water pumps.
 

Both of my 300ds have that same hole on top, chevy and ford put it on the bottom. My understanding of the hole is that it signals replacement time when water starts dripping due to worn out bearings / seals.

Thats how it's supposed to be, your not missing a plug or anything.

Thats a vent hole. If plugged, pressure of a spinning shaft would dislodge the seals.

Well I learned something today! Guess it would be bad to build any pressure between those bearings and seals!

It's called a weep hole. If the seals are leaking it will weep coolant through the hole to alert you of a bad seal (hopefully) before the bearings seize.

well now that's what I thought, differing opinions - which one is right? Maybe I already knew this!

I forgot to mention that there are two holes in the pump, one up top and one in the same location underneath.

perhaps the top one is to break the hydrostatic tension and allow the coolant to drip freely out the bottom.

Tom W

I think it's more because the pump's flange is symmetrical and can be clocked in most any position.

Wouldn't that weep hole that is facing up collect junk and cause problems?

I'd imagine so, but then again I didn't design it...

Not really. That section of the pump housing just is a dry area there simply for structural purposes.

Tom W