Yesterday afternoon while I was eating lunch we got a fire call so I hopped into my truck and naturally was out of the driveway as fast as I could go. Well about 3min into the drive I noticed that my engine temp light was on, but very dim and would slowly brighten then dim again. What could this be a sign of? Granted it did not have the usual warm-up time that it usually does but my temperature gauge was reading normal temps all the way, any ideas? It's a 1985 w/6.9

 

Here's a pic showing the locations of your coolant temp sensors:



Make sure both of the sensors are clean and tight. The temp gauge is notoriously inaccurate on our trucks.

 

I'm currently looking for a water temp gauge. What is the normal operating range for these motors?

 

Here's the temp gauge I installed on my bone stock 6.9l.

https://www.summitracing.com/parts/atm-2607/overview/

My truck runs 190*-205* depending on if I am sitting in traffic.

 

Ok, I found these that seemed reasonable for the time being. Come summer time I plan on getting a nice oil pressure, water temp, and egt gauge with a custom made pillar pod mount. But I feel that these will get the job done for the time being

 

anything under 240F