I just replaced the water pump, new belt, new thermostat and complete coolant change in my cat backhoe today. Ran it for 2 hours and it started overheating again over 220 degrees. I did NOT put the thermostat in wrong, but what i cant figure is how I can not see water moving through the radiator with a brand new CAT waterpump. Anyone heard of any internal restriction issues with this perkins motor? All the hoses are good and machine though old barely has 7000 hours. Any help would be appreciated. I did do a pressure test on radiator and no leak down detected. I am just plain stuck.
I take it that it wasn't overheating before you did all that work on it...? Is it possible you have air in the system somewhere..? Did you put about the same amount of new coolant in the system compared to what you drained out..? If the replacement water pump wasn't genuine Cat was it identical in all respects to the old one, by that I mean were the impellers the same, designed to spin in the same direction..?
Its a genuine cat water pump oem replacement same impellar. Coolant is full opened bleeeder in block its not air bound. Thermostat is installed in proper direction and the headgaskey is not blown. I was wondering if anyone had history with this motor and blockage or something that may cause this. I am a very experienced mechanic but this one has me baffled
Could the impeller on the new pump be loose on the shaft..?
No history with that motor, but radiators plugging up internally aren't at all uncommon, especially if they've ever been filled with hard water. Can you use a non contact thermometer to tell the temp of the water going out and coming back from the radiator? Nige, he said "overheating again" so I assume this is the same as before the work was done.
My bad. Missed that....... To the OP. Do you have an infra red thermometer..? If so try shooting the temp of the top and bottom radiator hoses when the engine is overheating and post the results here.