No water being pumped through engine-definitely water pump or what?

[Jr's Sho]

A car I'm looking at has a condition where it overheats due to no water being pumped through the engine. The belt is on there and the pulley is turning. What would cause a water pump from pumping water even when the pulley is spinning?

 

[Ishodu]

Is there heat? How did you find out that there is no water flow through the engine? Does the upper rad hose get hot?
If there is no flow it could be a stuck closed termostat, blocked passages, cloged rad, worn impeller on the water pump.

 

[SHO--ripper]

GO with the cheapest first. Replace the thermostat.

 

[yamahaSHO]

SHO--ripper:
GO with the cheapest first. Replace the thermostat.

If you are going to start with the T-stat, don't just replace it. Test the one you have FIRST. Put it in a pan of water, heat it up and see what temp it opens at.