View Full Version : cooling problem

11-09-2007, 03:29 AM
what is the best way to determine if a water pump is bad? and it's not leaking

Mike F
11-09-2007, 04:36 PM
Hi maze1202,

Water pumps usually fail in one of two ways:

The seal at the water pump shaft fails, causing coolant to flow out of the "weep hole" that's on the bottom of the pump housing, near the shaft. Sometimes this will only happen when the cooling system is under pressure, so, if you suspect a water pump leak, it's a good idea to get the cooling system pressure tested.
The water pump bearing(s) can fail. This will cause the water pump to lose efficiency, and it can also cause the seal on the shaft to fail (see above). To check the pump bearing, try to move the water pump pulley up and down (with the engine off!). If there's noticeable movement, the bearing is probably bad.

More information on water pump diagnosis can be found in the Haynes manual for your particular vehicle.

Thank you for your interest in Haynes manuals!

11-09-2007, 06:28 PM
Check for coolant flow, once the engine is warmed up and the thermostat is open you should feel the temperatures between upper and lower hoses equalize very quickly if the pump has good flow.