View Full Version : TR4/4A water pump mystery hole

02-09-2017, 03:48 PM
This is only the 2nd time I've had the water pump off in 40+ years but the first time I noticed the hole in the bottom (see pic). I think the pump may be a replacement cause there's no grease zerk on top ( or even a place for one) that all the illustrations I've seen show on an original. Not concerned about it cause it's obvously there for a reason, I just don't know what that is. Is it to shoot some sort of lube into the pump? Should there be a plug of some type in it that's gone missing? It's not threaded.

02-09-2017, 03:53 PM
Usually the hole in the bottom is to let water out when a seal fails. Otherwise the water could go where you don't want it!

02-09-2017, 03:58 PM
That is called the "weep hole".
The "weep hole" is there to allow any accumulated coolant to drain out of the WP housing and to protect the WP bearings from coolant contamination/damage.
If the WP seals fails, coolant will run out this hole, and it is time to replace the pump....


02-09-2017, 04:33 PM
FWIW Original pumps also had the "weep hole".

02-09-2017, 06:20 PM
Thanks for that info fellas! knowing what function a part plays is one thing but analyzing the part itself is a whole new learning curve.

02-10-2017, 12:53 AM
I have a few early pumps that do have the grease zerk and that hole is about 1&1/2" by 1/4".

02-11-2017, 04:24 PM
One more caveat: Some of the China knockoffs had the hole on the top!