This may be a stupid question to ask, but how would you know if your water pump has packed up?. I know they can start leaking which is obvious to spot, but that wouldn't stop the pump circulating coolant. How do you check that its still pumping the coolant around the engine, leak or not?

 

Cheers...

Top radiator hose connection will be hot and hard with pressure after the engine warms up. It will heat up suddenly as the thermostat opens. The rad can still feel quite cold but that is simply due to the thermostat only allowing just enough flow to maintain engine temp in this cold weather. The heater should also be heating. If you had no flow the engine would simply overheat very quickly. Even a stuffed leaking water pump tends to pump fine. Usually it leaks due to its seal and bearing / bush being ruined. The pulley might have movement in it indicating worn bearing / bush.

 

Apparent leaking water pump on a zed is often the 2 short head feed water hoses directly above the pump - when they go they make it look like the water pump is leaking when it isnt.

It's not necessarily that obvious if the water pump has a leak. There is a small drain hole at the bottom, you can get a small leak out of there which is enough to cause overheating probs without being obvious. i only knew mine was leaking when I had it changed when the cam belt was done, and the staining around it gave the game away. Oh, and the fact it now runs absolutely rock steady on half way up (needle horizontal) :headvswal

Water pump leaks usually show themself in the early stages by leaking after the engine is switched off after a run, often returning to the car after filling with petrol etc. you see a puddle under the car.

 

If the pump was not circulating due to say of a broken impeller ( seen this once in eight years!) then the engine would overheat in just a few minutes.

 

As correctly said the two small hoses that sit over the top of the water pump can leak and the leak will run over the pump, however these will always leak when the engine is running so there is the clue to what the problem is.

 

If in doubt strip and inspect because overheating is the no1 cause of zed engine failures.

 

 

Hope that helps

 

Jeff TT

Water pump leaks usually show themself in the early stages by leaking after the engine is switched off after a run, often returning to the car after filling with petrol etc. you see a puddle under the car.

 

If the pump was not circulating due to say of a broken impeller ( seen this once in eight years!) then the engine would overheat in just a few minutes.

 

As correctly said the two small hoses that sit over the top of the water pump can leak and the leak will run over the pump, however these will always leak when the engine is running so there is the clue to what the problem is.

 

If in doubt strip and inspect because overheating is the no1 cause of zed engine failures.

 

 

Hope that helps

 

Jeff TT

well said

 

yup get it diagnosed before any damage is done,tolerances are tight on the 300zx and having ally heads they can warp easily so get the front stripped asap and find the fault,on removal of main water pipes,sometimes the gasket seal between them can fail causing leaks so whilst there off inspect the 2short hoses for splits