Temp reads 220 after warm up and regular driving, 6.2 Diesel

[bigjeepinmike]

Temp question. My 1983 with the 6.2 diesel shows 220 on the gauge with normal driving. I can open the hood and handle the top hose easily as well as remove the radiator cap with no excitement. If I stick a meat thermometer in the radiator opening the temp barely reaches 170. Whats everyone thoughts.

 

[ChuckN]

Temp sensor is off and no longer accurate?

 

[ChuckN]

Or, perhaps get an infrared head sensor and aim it at the cylinder head or intake manifold. Is the sensor that feeds the gauge info just a one wire input?

 

[bigjeepinmike]

Yeah, single wire, under glow plug on cyl 1

 

[Grit dog]

Meh 220 is the new 170…lol.
Good news is, you’ve verified it’s not overheating.
I’d slap a new temp sender in it.
If not, you now know where “normal” is on the gauge!

 

[Blue Ox]

They're supposed to run at 195° . As above, I'd verify with an IR gun. Could be the sender, but could also be a faulty resistor on the gauge.

 

[scrap--metal]

My 1983 with the 6.2 diesel shows 220 on the gauge with normal driving.

Has it always done this since you bought the truck?

There are different temp sending units that produce different resistances. I'd guess that it has the wrong sending unit in the engine. I know I've had to get different temp sending units to get my small block temperatures to read accurately. I'm guessing the 6.2 diesels are no different in that respect.