New to the forum, have owned Ford trucks since early 80's. Truck in question is a 2000 F150 5.4. 171200 miles. I'm having some over heating problems, I live about 8 mi. From work location, travel to work no problems, truck will operate at normal operating temp. When leaving work if I have to fuel or make a quick stop before truck reaches normal temp then travel home truck overheats. A five Minute stop to let cool and I'm good to go, can travel many miles without issue. On several occasions I have traveled home from work and have some coolant overflow from coolant tank. I've changed the thermostat and coolant about 1000 miles ago with no change. I'm leaning towards water pump, flush, maybe hoses. Am looking in the right direction? not much left to change. Looking for some input, thanks Mike

 

What was the condition of the coolant before you changed it? Any discoloration at all?

 

It was about 4 yrs old, I changed it when I had to replace the intake, but there was some discoloration not bad.

 

I suspect it's probably the water-pump. Might as well do all the hoses/clamps too.

 

Any other opinions out there?

 

I had an issue with the cooling system on my old Explorer. It turned out the weld that holds the baffle plate in the thermostat broke and sometimes the plate would just close off the flow completely and other times it would work normally. I had never seen that before so no idea if that is unusual or not.

 

That's a new one for me.

 

Ok replaced water pump, lower rad hose all last weekend. Today a short drive, engine didn't get to operating temp, two hour wait before heading home look down and temp light is on gauge is showing hot, pull over pop hood to do a visual, nothing. Slam hood get in truck turn on key and temp is normal, 5miles home no problem. Same as original post. New thermostat bad? What gives?

 

Have you checked the fan clutch?

 

Haven't checked it, symptoms lead me towards something more internal. Any tips on checking the fan clutch?