2000 S Type 4.0 V8 Overheating

(sdmarm) #1

Have replaced “cheap” Ford plastic thermostat housing with aftermarket metal version / new thermostat / radiator flush / new coolant removed “air” - engine still overheating . . . . I turn on defrost to high and temp returns to normal. Can anyone suggest other trouble areas I should look into for solution??

(Geoff Allam) #2

Has the water pump been replaced. Wher I owned a 2000 years ago it was a problem I had a couple of times. Original impeller was plastic. Replacements now have an aluminum one.

(sdmarm) #3

Hello Jeff . . . please forgive delayed reply. I have not had time to do further work toward issue. UPDATE: have replace several “plastic” hose connectors (Clacked and leaking), several hoses, radiator flush, and still overheating. Have not tackled water pump yet.

Of note: when engine comes up to “normal” temp, all of the hoses are hot with the exception of the bottom hose coming from the radiator?? Also, when I drive and keep mph below 30 the temp does not rise. Shortly after I enter the main highway from subdivision and accelerate to 50+ mph, temp will red line. Defroster quickly restores temp to “normal”


(Geoff Allam) #4

If the bottom hose is not hot it indicates that fluid is not moving through the radiator. Makes the thermostat suspect. The temperature dropping when defrost is engaged is likely to the auxiliary heater pump kicking in and the heater core acting to help cooling. If it was my car the first thing I would do is to change the water pump, replace the thermostat and swap the plastic thermostat housing for an aluminum one if it has not already been done. None of thise parts are terribly expensive and all are known problem areas.

(Geoff Allam) #5

Sorry. Just noticed that you had changed the thermostat and housing. My next move would definitely be water pump.