I have a 1998 Ford Expedition 4WD, 4.6L Engine that does not get up to normal operating temp.

1. System has been flushed and new thermostat installed.

2. No known coolant leaks and coolant level normal

3. No signs of oil in coolant nor coolant in oil

4. Fan clutch recently replaced which made some improvement

5. New Temperature sending unit installed and tested, electrical good. Engine get only to approx. 170 degrees (measured at coolant manifold near where temp sending unit is located). Main Rad hose measures about 170 as well.

6. All heater core hoses get hot (front and rear).

7. I also have little to no heat front or rear.