+1 to the others suggestions to CONFIRM there's isn't any air trapped inside the motor. The V6 coolant refilling procedures need to be followed exactly.
http://www.allfordmustangs.com/foru...lar-rpms-showing-hot-post2604913.html#2604913
Why is this important!! Because on the older V6's with an ECT sensor when air is trapped inside the motor, air will be in contact to the ECT instead of coolant. This will make the ECT read LOW. The motor will be overheating while the dash gauge says "I'm OK".
Turning the AC reduces the problem because when the AC is on, the cooling fan runs all of the time. It may be possible that the PCM is turning off the cooling fan because the ECT is reading low (see air touching the ECT sensor).
Next thing. Today's cars are designed to work with the water flowing through the heater core all of the time. Do not cut and block the heater hoses to bypass the heater core. Loop them instead.
Next CONFIRM that the cooling fan is actually working. Should be easy to do as the V6 has a single speed cooling fan. Turn the AC and confirm that the cooling fan is actually running.
Now here's where it gets interesting. In the V6 the cooling fan is protected by an automatic resetting CIRCUIT BREAKER!!!! This means it's possible for the cooling fan to appear to work. Stop working and then begin working as if by magic.
What's the most common reason for the CB to trip? Bad fan bearings causing excessive power draw. How does the fan feel when spun by hand? Does it spin freely? Any "growling" noises while it's running?
I strongly suggest starting with the basics.
If after doing all of this it still overheats, pull over and check the cooling fan. The CB may have tripped.
http://www.allfordmustangs.com/foru...lar-rpms-showing-hot-post2604913.html#2604913
Why is this important!! Because on the older V6's with an ECT sensor when air is trapped inside the motor, air will be in contact to the ECT instead of coolant. This will make the ECT read LOW. The motor will be overheating while the dash gauge says "I'm OK".
Turning the AC reduces the problem because when the AC is on, the cooling fan runs all of the time. It may be possible that the PCM is turning off the cooling fan because the ECT is reading low (see air touching the ECT sensor).
Next thing. Today's cars are designed to work with the water flowing through the heater core all of the time. Do not cut and block the heater hoses to bypass the heater core. Loop them instead.
Next CONFIRM that the cooling fan is actually working. Should be easy to do as the V6 has a single speed cooling fan. Turn the AC and confirm that the cooling fan is actually running.
Now here's where it gets interesting. In the V6 the cooling fan is protected by an automatic resetting CIRCUIT BREAKER!!!! This means it's possible for the cooling fan to appear to work. Stop working and then begin working as if by magic.
What's the most common reason for the CB to trip? Bad fan bearings causing excessive power draw. How does the fan feel when spun by hand? Does it spin freely? Any "growling" noises while it's running?
I strongly suggest starting with the basics.
- Loop the heater core (don't block the heater core lines)
- confirm the correct 50/50 coolant mixture
- confirm the radiator pressure caps holds pressure
- re-fill the system following the V6 coolant re-filling procedures
- Confirm that the cooling fans runs
If after doing all of this it still overheats, pull over and check the cooling fan. The CB may have tripped.
