'75 W116 Water Pump. 3.5 V8 - PeachParts Mercedes-Benz Forum

Mad Mick · #1 11-04-2006, 10:30 AM

Hi Folks.
Have a small water leak which seems to trace up to the underneath of my water pump. There is a small bored hole here that appears to be the cause of my leak.
Any ideas on what this hole is for and why it would leak.
Seems to me like a new pump will be required and I hope this is not too much of a PITA to replace.

Thanks.

Mad Mick.

Tomguy · #2 11-04-2006, 11:00 AM

This hole (called a "weep hole" is on every water pump I've ever seen and I believe the purpose is to help keep the bearings of the pump lubed. A sign of a pump about to go is often an overleaky weep hole. Coolant is often visible from the hole under normal conditions but, if you're noticeably dripping from it, your pump is probably about to die.

Mad Mick · #3 11-05-2006, 06:50 AM

Thanks Tomguy.

I'll order one tomorrow.

t walgamuth · #4 11-05-2006, 07:22 AM

actually i think it is solely for the purpose of telling you that the seals are gone.

yep....time for a new one.

tom w

Tomguy · #5 11-05-2006, 01:08 PM

Tom: Personally, I'm not 100% sure on its purpose, but on 3 water pumps I've replaced, they all leaked from the weep hole - one resulted in massive failure - the pump shaft broke resulting in a nearly exploding radiator, somehow the fan didnt puncture it at all! I didnt replace that pump because the water pump was leaking a coffee can of coolant every time I parked it, and then suddenly stopped. 3 days after it stopped leaking (about 30 miles tops) - poof!