How can you tell if your water pump is on the way out

[aceventura]

When driving along normally, the temperature gauge sits where it should. Going up hills, sitting at lights etc, the temperature goes up to about half way, and the fan kicks in - all good.

However, after going up a hill then cruising again, it is taking much longer than it used to for the temperature to come back down again.

The thermostat is new, as is the sender. The radiator doesn't appear to be blocked inside or out.

Causing no hassles at the moment, but I am interested if it is indicative of a developing problem.

[GTP 85]

- rusty water leaking out from under the pump pulley/ or general loss of coolant
- rattling or squeaking from the pump area, with overheating

[alex2_s]

mine was cooling normally but making an intermittent 'click click click' noise at idle (ie. bearing going). it wasn't in speed with the engine.

[aceventura]

Thanks guys - Mine certainly isn't displaying any of those symptoms.

But I seem to remember some posts where people report when they pulled the water pump out, the fins were basically missing due to corrosion. This would hinder circulation of the water.

[hako]

If the impeller fins on the waterpump were corroded off it would mean they were not using the proper coolant - if you're running proper coolant it should be OK.

[Croydon]

Hate to tell you - I understand this is normal. Mine does it too!

[dons vs]

most water pumps have a small drain hole just under where the shaft comes out of the housing, this goes into a chamber behind the bearing and seals.
when they start to go you will get a small amount of coolant leaking out of this hole, this is first signs of water pump becoming cactus, might be old or belt might be to tight?
When the bearings go they tend to make a fairly annoying rattly noise as well.

The blades can start to corrode away to nothing which will cause a massive loss in coolant flow which will cause over heating, this can be caused from a few things.
bad/old coolant
no coolant
mixed coolants or additives which shouldn't be mixed
bad engine earth connections

if you stuck in a new thermostat, maybe pull the rad out and give it a pressure test from a proper radiator joint, that will make sure its not blocked as although there may be flow through the radiator it may not be going through the hole radiator getting max surface area.
if still nothing then just replace the pump anyway, there not expensive.
Use good coolant and make sure you flush and bleed the system well, eg stick a garden hose on one of the heater lines going into the firewall that is opposite direction of flow, this can get rid of any blockages in the block, head, hoses and heater core.

after those few things it should be pretty sweet.