What is normal operating temperature?

The temperature gauge on my 2006 Ranger 2.3L is only 1/4 inch above the cold mark. I decided to replace the thermostat. I bought a Motorcraft 194 degrees, per spec…

Now the temp Gauge is close to the middle. I connected my Scan gauge to read the water temp. At idle in my driveway the temp is 215F and when I drive on some smaller hills the temp goes up to about 240F. The gauge stays in the middle.
Is this a normal operating temp ? At what temp should I worry?

215 is a little high for idle. 240 is more than a little high for down the road. You should be idling right at 195 and maybe 200 down the road. This assumes the sender in the engine sending info to your scanner is accurate. The gauge is reading “normal” but your scan readings need to be compared with another temp reader. I would suggest you use a non contacting IR temp gun.

It depends on the operating conditions under which the vehicle is driven.


According to what I see the thermostat should begin to open at 194 F, and fully open by 223 F.

I don’t think the temperatures you are measuring indicate a malfunction. Make sure to use the proper coolant spec, replace it periodically, and bleed it of any air pockets, including in the heater core circuit. I presume you’ve already done that. Is the engine cooling fan turning on and spinning like a banshee when the coolant gets hot? If all that’s ok, probably no worries.

2001-2011 Rangers with the 2.3l Duratec engines use a CHT(cylinder head temp) sensor NOT an ECT(engine coolant temp) sensor, so that’s what you see on the OBD reader
And 230 to 250degF is about right, that’s NOT coolant temp, its head metal temp.

The dash gauge uses a 12volt temp SENDER, not a sensor, 1/2 way is about 205deg, just below 1/2 or 1/2 is normal on the 2.3l Duratec


My 5.0 also uses a CHT sensor and I don’t see 240 down the road nor do I see 215 at idle, but it is a different engine. But it has no sender or sensor for coolant. The gauge reading is software generated.

If no other symptoms I’d put the scanner away for now and drive on.

Thanks you for the information. Very helpful.