2510 water pump will not pump water

[Craig Tull]

The strangest thing I have ever seen, the water pump on my newly squired 2510 will not pump water. I removed the pump cover and all looks OK impeller looks fine and turns with the engine, removed the thermostat and with the engine running and the top hose removed from the thermostat housing I can pump water through the radiator and engine with water coming out of the thermostat housing but as soon as I stop pumping water into the top hose the flow stops, it should continue until the water is all pumped out of the radiator but no, there are no leaks, the top hose does not heat up indicating flow until it gets overheated and then pushes the water towards the radiator cap under the seat as the pressure is released.
Dangdest thing........
Any ideas??
Craig....

[okieduc104]

I would believe that your coolant system is air locked, this is common with the liquid cooled Mules, the coolant tubes have air in them and the water pump won't pump air. The engine will overheat and then the steam pressures up and boils out the radiator filler. Lift the front wheels up a foot or a foot and a half so that the radiator filler is quite a bit higher than the waterpump and engine. Pull the radiator cap and slowly fill the radiator to the top with 50-50 distilled water and coolant mixture, wait a half hour and do it again, and again. This should let the air bleed off and exit at the radiator filler. Does the 2510 have the plastic auxillary coolant reservoir mounted above the filler level of the radiator? If it does you will need to completely fill the radiator, tighten the radiator cap, then with the overflow connected to the auxillary reservoir fill it up to the full mark.

[cookie_monster]

Lifting the front works...but it's not foolproof.

On the intake manifold of the 2510 is a black 10mm headed bolt. Remove it (with the engine cool. Remove the front radiator cap and the filler cap under the seat (both of them). Fill the center filler until coolant runs out of the intake manifold. Reinstall the bolt. Then continue to fill until the coolant runs out of the front radiator. Reinstall the front cap...while the coolant level in the radiator is completely full. Then continue to fill the center filler until it's full. Leave the cap off, start the engine. It should bubble a little for a short period of time, then the bubbles will stop. If it doesn't stop bubbling within about a minute, a head gasket is probably leaking (common). Once the bubbling goes away, reisntall the cap and fill the "puke" tank...I like to FILL it (all the way), let the engine run until the fan comes on, shut it off, and leave it be until the next day. THen check the puke tank before starting the engine. If it's overfull...drain (or suck) a little out. If it's low, add a little. If its OUT, there is still air in the system or the system can't hold pressure for some reason (usually head gasket(s) )