XJ overheating

my buddies got an 91HO with an overheating problem. Weve done all the usual stuff, checked the gauge, 4 core radiator, high flow thermostat housing, heavy duty fan clutch, etc.. we think it's got to be in the engine- any thoughts?

rick88yj

[xjy173]

Have you checked to see if the water pump is pumping? You can do this by squeezing the top hose with channel locks after the thermostat opens and listening for flow thru the hose. If no flow then the pump impeller is bad and the pump has to be replaced. Good Luck!

we've replaced just about every componet possible on the outside of the engine

rick88yj

[Andytron]

How do you know it's overheating? Is it loosing coolant out of the resavoir? Does the gauge say so? Did the idiot light come on? If it is either of t he last two try replacing the temp sending unit. Or go get a cheap mecanical gauge and test it that way. Had the same prob and it worked for me. Later, Andy 89XJ 4.0 5-speed