Unexplained High Temp reading

[DFendersExpy]

Ok This is bugging me out... I finally Got my truck Back for the Dealers which they had to replace the Smart Junction box with a lovely cost of $978.58 yes that hurt the pocket ....
Anyway he is my issue the truck runs fine for the most part, But after driving around for a bit ( no Major drives) I shut off the truck for a few mins 10-15 mins tops when i restart the truck and its running I get a high temp reading for a few mins, then it will drop to normal temp readings... Can anyone help me with this one....

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[stamp11127]

One of three things:
1) The gauge reading is accurate and there is high temp at the sending unit. Check coolant level for proper fill and for any air trapped in the system.

2) Low oil level - check the level

3) The gauge reading is inaccurate. In that case you would test the sender, gauge and harness.

The higher end scanners will give the sender voltage readings which will make this quick and easy if you have access to one. Check with your local auto parts stores to see if their scanner will read specific sensors, you might get lucky.

I have an Explorer that does something similar to that but instead gives a low reading.

 

[DFendersExpy]

I'll check on it thanks

 

[copper08]

Another couple of reasons also would be blown head gasket or a faulty gauge ground.
Just to add another place to look.

 

[DFendersExpy]

Another couple of reasons also would be blown head gasket or a faulty gauge ground.
Just to add another place to look.

Thank god it wasent that... Turns out i was just low on coolant

 

[DFendersExpy]

Thank god it wasent that... Turns out i was just low on coolant

OK now its happening again ...Last several days I will drive for a bit not long just around town, I'll shut it off for like 15-25 mins go to start it up and that high temp reading all over again. But if I shut it off then turn it back on its back to normal ... What the heck can be wrong.... Coolant level is fine . I check what i could on the grounding looks ok I even Added a 0 gauge wire for grounding to the body for added measure from the battery.. I dont have the means to check or even remove the CHT sensor... I was wondering can I bypass it somehow... Maybe unplug the CHT sensor and Plug it to a new one without taking apart the intake to get to it? Can this be done? As much as I love Expeditions and Ford for that matter this one has been a nightmare since i purchased it a month ago... I'm not giving up on it yet... HELPPPPPPPPPP!!!!!!!!!