While 110 degF isn't the 190+ degF it should be at, it is certainly drivable.
You can start an engine and drive vehicle when it is -30 degF outside way before engine even gets close to 110degF, or where it should be at 190+.
Think about it, what he said would mean no one could drive their vehicle for at least 10 minutes after starting it..........huh???
So tell him to go back to mechanic school at Micky Mouse High or Chevrolet, because he missed a day, or two.
The Thermostat sets the minimum operating temp on an engine, on your 3.0l the thermostat is in a housing connected to the upper radiator hose(engine end), it should have a 192degF or 195degF thermostat in it.
A Thermostat has a bi-metal spring that pulls open a valve as the spring is heated, valve allows coolant to flow out the top rad hose, it is a pretty simple device.
Spring is calibrated to temp, so you can get 160degF, 180degF, 190degF and even 200degF thermostats.
The 3.0l gets best MPG and oil cleaning at 200-220degF, so you want a 192 or 195 degF thermostat.
So Thermostat is there to block coolant from flowing thru the radiator, radiator is only used when EXTRA cooling is needed.
Water pump circulates coolant thru the engine, not the rad, when thermostat opens coolant will flow out of upper hose and push coolant out of rad thru the bottom hose and back to engine, radiator is not a required path for circulation, it is an available path.
Most engine designs require extra cooling when outside temps are warm, above 40degF.
But some engines never use the rad in the winter, just some residual flow and heat transfer, some people even need to block the front of the rad to prevent air circulation from cooling the engine bay too much in the winter.
You have probably seen that on the front of Semi-trucks, the zippered or snap-on flaps over the front grill.
So first stop would be to check if upper rad hose is heating up with the engine, it shouldn't.
Engine temp should be 185/195 degF before upper hose starts to get warm, so 8-10 minutes after staring cold.
If upper radiator hose is heating up with the engine that means thermostat is stuck open or is missing.
Now 110degF is not exactly cool, lol, so you should feel some heat from heater.
Feel both heater hoses at the firewall, with inside control set to HOT both hoses should be about the same temp, warm to hot, that means heat control valve is allowing coolant to circulate thru the heater core.
If both hoses are cool or one is it means coolant is not circulating thru the core, check the valve, it is on the heater hose.
And since this is a new truck to you there is also a chance previous owner by passed the heater core because of a leak, so he connected OUT and IN connections from engine together, follow the hoses make sure both are connected to the engine and/or water pump.
Inside the cab heater unit is the Blend Door, this door opens and close to allow heat and cold, the actuator on this Blend Door is a known issue on the Fords.
Google: 1999 ranger blend door
Last edited by RonD; 01-17-2015 at 02:36 PM.