2000 Quad Cab 4.7
How do you check water pump operation? Service manual says to take out enough coolant to see upper rows in radiator, but with the radiator cap in the upper hose, how is this possible?

 

That is what it says and you can't really do that. If you have heat in the cab then it is working.

Why do you think the water pump isn't working?

 

Couple years ago had overheat problem. Replaced everything, started with a flush, then new tstat, then water pump, finally checked radiator. It was plugged, so I put a new one in. Took a rock hit and started leaking. Put some Bars Leak in and took care of that. Last week, took another rock hit, put in some more Bars Leak and took care of leak again, but started running warm. Did another flush and tstat. No better, and leak came back. Took out radiator and shop said can't fix it, so I put a new one in. Still running warmish. Never did get it "hot". Could regulate engine temp somewhat with the heater temp control. Running down highway it'll get around 220, crank heat up will drop temp 10-15 degrees. Drive around town it won't heat up past 205 or so. Can't see any oily film in the coolant or any moisture on dipstick, so I'm hoping it's nothing to do with the head. Engine temp is pretty relative to the ambient temp.

 

Are you sure it is the correct radiator? Right number of rows, etc? The new thermostat may not be working right either.

It doesn't sound typical of a head gasket.

 

def sounds like bad/wrong thermostat or too small radiator. You did burp the system of air as usual yes?

 

Might have something to do with adding double dose of a product that can cause clogs and impede flow. You'd have been better off adding JB Weld from the outside, rather than Bars Leak on the inside.

To check water pump, you take off the belt and spin it by hand. The bearings going is the only way I've heard of them failing. They do chatter and weep long before failing.

 

Everything back to normal. Must have been just some air trapped in the system. Had coolant in an out of this truck a few times, always have trouble getting air out!