Temp issue....

[rusty ol ranger]

Im *thinking* its minor...but want to ask...

First long trip with rusty 2.0 today (87 2.9) all was well when driving, in town, etc. But i stopped at kind of a long red light and the temp gauge shot up to the top of the normal band, then dropped right back down to just below the middle.

It did this every time it idled for 60 seconds or so after driving, but it always went up fast then back down.

Then when i got home i pulled in driveway and it shot up again, i let up the clutch and stalled it (oops) then fired it back up immediatly and it sat and idled with the gauge sitting right where it should...

Im wondering if its electrical, or maybe an air bubble? I changed the t stat (180* failsafe) and temp sender, and had to add maybe a quart or 2 of coolant afterwards. But ive never gotten a bubble like that before...

Id also like to add that the cooling system on this thing is pristine and the antifreeze green as grass. So i doubt its actually wanting to heat up, plus, it was only 65*

Input?

 

[fastpakr]

If it's not an air bubble, the next thing I'd be inclined to suspect is the water pump impeller.

 

[adsm08]

Water pump or fan maybe.

 

[rusty ol ranger]

Ah, didnt think of the water pump impeller. Ill check into that

 

[rusty ol ranger]

I have a feeling its electrical.

This morning i drove it to work and all the gauges ( went up in unisen toward the top of normal (bout 3/4 way) and the fuel gauge magically went up 1/4 tank as soon as put a high draw on the alt (wipers, blower, headlights, etc). I stopped at work and let it idle while i warmed up the semi, after killing the lights and blower the gauges returned to normal.

Every older Fseries ive had has done this, not sure why. I remember rusty#1 did funky stuff to.

Ill keep an eye on it, but i dont think its for concern