2000 FORD EXPEDITION OVERHEATING....changed thermostat,radiator cap, confirmed fan clutch is working, no radiator leak noted, changing coolant temperature sensor as a type...water pump not leaking or "making noise"...when changed thermostat noted very rusty water and in hoses...did radiator flush and new coolant....help, wat else, change water pump?

Begin with the basics....
INSPECT COOLANT LEVEL,
Low ????,PRESSURE TEST SYSTEM,
PRESSURE TEST RADIATOR/EXPANSION TANK CAP,
INSPECT DRIVE BELT(s),
INSPECT COOLANT HOSES,
INSPECT HEATER HOSES,
INSPECT BYPASS/MISC. COOLANT HOSES/PIPES,
TEST THERMOSTAT OPERATION,
INSPECT RADIATOR COOLING FAN(s)/CLUTCH OPERATION,
INSPECT CONDENSER/AUXILARY COOLING FAN(s) OPERATION(s)
INSPECT RADIATOR & CONDENSER FOR DEBRI,
OBSERVE COOLANT TEMPERATURE GAUGE OPERATION,

If you need further help, reach me via phone at https://www.6ya.com/expert/ralph_2f0886b7d6af32ce

A true overheat is when the coolant is bubbling back into the coolant recovery tank. #1 radiator cap not holding pressure #2 stuck thermostat #3 restricted air flow #4 bad fan clutch #5 bad waterpump #6 restricted water flow in radiator #7 blown head gaskets this is the end results to a overheated engine .

Check the fan clutch and see if its engaging ! Start the motor and let run a few minutes and turn vehicle off while observing the fan blades if it free wheels when the motor is turned off then its bad ! Also take the radiator cap off with it cold and full of fluid and start the car - does coolant imediately shoot out if so the head gaskets are blown !

Here are a few things to try. Check your Radiator cap pressure as a weak cap will boil over more quickly. Replace your Temperature sending unit. There may be 2, one is for the dash gauge and the other is for engine control. Unless you have other signs of overheating you may not be overheating at all, just a bad sender.

Next, the cooling fan clutch is what the fan blade is mounted on. This is checked by using a Timing light with a RPM tach made into it. The fan clutch "locks" at a variable temperature. In cold weather it slips internally. In hot weather it engages or "locks". A mechanic measures the RPM of the blade to the RPM of the engine. This tells if the fan clutch is slipping too much internally.

Before considering a new water pump try a free scan at Autozone or Oreillys. If your Catalytic converters are plugged the engine will overheat. You should have a Code for this problem in the onboard computer. About all you can try after this is to remove the Thermostat completely and see if the engine still overheats.

You will have to replace the New Thermostat again because the other engine controls will not work right without it. But without the thermostat you can test for collapsed Radiator hoses at say 2500RPM or above. Thats about all I can think of, the water pump would cost the most. The cap, sensor-sender, fan clutch, and hoses are not that expensive.

CHANGE THERMOSTAT AND RADIATOR PRESSURE CAP.CHECK COOLANT LEVEL.MAKE SURE YOU HAVE 50/50 ANTIFREEZE AND WATER.MAKE SURE COOLING FANS COMING ON WHEN ENGINE REACHES 190 DEGREES.TO SEE IF COOLANT FANS RUNNING TURN ON CAR AIR CONDITIONER TO SEE IF FANS RUN IF NOT CHECK COOLING FANS FUSES.IF FUSES GOOD I AM LOOKING AT A FAULTY COOLANT TEMPERATURE SENSOR.IF ALL IS GOOD.NO LEAKS AT RADIATOR HOSES + HEATERS HOSES. NO LEAKS AT WATER PUMP WEEP HOLE OR GASKET.NO LEAKS AT RADIATOR.LAST RESORT CHECK ENGINE OIL. IF LOOKS LIKE MILK SHAKE YOU HAVE LEAKING HEAD GASKET.THAT WILL CAUSE ENGINE OVERHEATING.

change the thermostat

1 Inspect Cooling System Mix Coolant level low or flow is restricted. 2 Inspect Belt Incorrectly routed, adjusted, tensioned, missing, or worn water pump belt(s). 3 Inspect Oil Pan Gasket - Performance Ruptured, cracked or leaking radiator hose. 4 Inspect Radiator Cap Worn or damaged radiator cap 5 Inspect Thermostat Thermostat stuck closed 6 Inspect Fan Blade Broken, missing, or defective fan blade(s). 8 Inspect Water Pump Damaged, worn or leaking water pump. 9 Inspect Intake Manifold Plenum - Perform Leaking water pump gasket. 10 Inspect Cooling Fan Control Faulty cooling fan control or circuit. 11 Inspect Cooling Fan Switch - Radiator Faulty radiator cooling fan switch or circuit. 12 Inspect Engine Temperature Sensor Faulty engine temperature sensor or circuit. 13 Inspect Temperature Switch Damaged or faulty temperature switch or temperature switch circuit. 14 Inspect Fan Clutch Worn, loose or faulty fan clutch. 15 Inspect Ported Vacuum Switch Damaged, leaking, or faulty ported vacuum switch. 16 Inspect Radiator Obstructed radiator core or radiator cooling fins. 17 Inspect Head Gasket - Performance Head gasket leaking coolant into cylinders

2 Inspect Belt Incorrectly routed, adjusted, tensioned, missing, or worn water pump belt(s). 3 Inspect Oil Pan Gasket - Performance Ruptured, cracked or leaking radiator hose. 4 Inspect Radiator Cap Worn or damaged radiator cap 5 Inspect Thermostat Thermostat stuck closed 6 Inspect Fan Blade Broken, missing, or defective fan blade(s). 8 Inspect Water Pump Damaged, worn or leaking water pump. 9 Inspect Intake Manifold Plenum - Perform Leaking water pump gasket. 10 Inspect Cooling Fan Control Faulty cooling fan control or circuit. 11 Inspect Cooling Fan Switch - Radiator Faulty radiator cooling fan switch or circuit. 12 Inspect Engine Temperature Sensor Faulty engine temperature sensor or circuit. 13 Inspect Temperature Switch Damaged or faulty temperature switch or temperature switch circuit. 14 Inspect Fan Clutch Worn, loose or faulty fan clutch. 15 Inspect Ported Vacuum Switch Damaged, leaking, or faulty ported vacuum switch. 16 Inspect Radiator Obstructed radiator core or radiator cooling fins. 17 Inspect Head Gasket - Performance Head gasket leaking coolant into cylinders here is a list of things to check Shaun

this may be a cluster,wiring or sending unit problem.ask your dealer how hot the engine was getting,with a scanner they can tell what temp the coolant is at.yes your temp gague is rising but is the engine even overheating ?

1. start the engine and leave the radiator cap open.
2. put a cardboard cover or a rug in the front of you radiator.
3. let it runs 20 minutes or more, see if it is overheated and see the water or coolant in the radiator circulated or not. If not, as soon as you have already changed water pump. thermostate and check the hoses, no leak, I think your radiator was blocked.

Did you put stop leak before?