Water Pump Question

[Brakin80]

I've never had cause to take apart our water pump, but thought I would pick up a spare. Just received an NOS Unipart water pump for our 1960 BN7. Noticed there was a hole in the pump body casting. (You can see the spindle assembly inside.) I haven't checked the one in the car to see if it's the same, but why would it be there? Is it by design, or is it a flaw? Thanks.

 

[Ralph F.]

I don't think you will find it on modern stock, but on NOS pumps the hole is known as a weep hole. The theory is that a small amount of coolant leaking past the shaft seal will help to lubricate it, and you can wipe the excess during regular maintenance. When weeping (from the hole) becomes excessive, you know that it is time for a new pump.

 

[Brakin80]

Once again, it blows my mind that someone on this forum knows stuff like this! Thanks Ralph.

 

[RF Thom]

Brakin80

The weep hole, some pumps have two [2], main function is to provide a path for any weeping/leaking coolant to escape rather than being forced into the pump bearing. Coolant systems operate under pressure, with cap ratings up to 14 psi, however with closed thermostat and higher RPM's the pump can produce a head pressure of up to 45 psi. If coolant is forced into the pump bearing, it will cause bearing failure and allowing the fan to launch into the radiator. The bearing does have end seals but they're to retain the lubricant and are not a pressure seal to keep coolant under pressure out.

Regards, Bob

 

[Skip & Lynne]

It was always my understanding that the weep hole was so you could tell if the pump seal had gone bad and the pump needed replacement. Skip

 

[RF Thom]

Skip

You would be surprised how fast that bearing, spinning at 4,000 RPM, under load, without lubrication can burn up. Remember the load is not just the water pump but also the fan and the generator - the belt is pulling these loads not pushing as the slack is between the cr'shaft pully and the generator. Water pump with fan attached can draw as much as 14 HP [ think of size of a 15 HP electric motor and equate that to the size of the w/pump bearing]. You can't inspect the weep holes when your driving at 60 MPH+, and you don't want the fan to go into the radiator - you'll have even a bigger bill. I've even seen the fan flop around and slice through the hood [ sorry bonnet ].

Regards, Bob

 

[Skip & Lynne]

Bob what I meant is that long before the bearing goes you will notice water puddling under the car, usually the weep hole is on the bottom of the water pump neck and the water drains down the front of the block.. I didn`t look at my BT-7 but I have seen this on several Chevys and Fords and it has saved me a time or two.

 

[Keoke]

That is correct Skip, by the time the pump begins to leak you will have a stain under the weep hole on the pump and down the front of the engine.Similarly, you should see water spots on the side panels of the engine compartment and on the underside of the bonnet. Should you see water puddling on the floor you are way overdue for a pump change.---Fwiw---Keoke- /ubbthreads/images/graemlins/yesnod.gif /ubbthreads/images/graemlins/grin.gif

 

[Dave Russell]

What Bob is saying is that with the hole, there is quite a bit of time between the first leak & complete bearing failure. If the hole wasn't there, a minor seal leak would take out the bearing very quickly, with very little warning.
Water pump lubricant in the coolant is for the benefit of the seal, not the bearing.
D