temp gauge needle barely moves

[BlaineM]

Just bought this truck

97 ranger xlt super cab
4.0L,
5 speed manual Mazda trans,
2 wd

After the truck is plenty warm and has been driven for 1 hour the needle on the temp gauge has barely risen above the lowest mark.

The coolant is right up and the heater puts out plenty of heat. The needle does not fluctuate during driving. It just creeps slightly off the lowest mark and stays there.

There are no other issues with this truck that I know of yet other than; a few times during the day the "door ajar" light lights up on the dash and the interior light stays on, even when the doors are firmly closed. Where is the door switch?

With regard to the temp gauge I am considering the usual suspect (thermostat) but am wondering if the temp sender could be faulty. Where would that beast be located? Has anyone else had a similar problem?

 

[MAKG]

FIRST thing, make sure the engine is full of coolant.

The thermostat -- and temperature sender -- both live at the highest point in the cooling system, and will read anything -- including dead nuts cold -- when not immersed in coolant. I believe the heater is always in service in this vehicle (no bypass).

 

[BlaineM]

Thanks for the quick response. Where does the temp gauge needle usual reside during normal operation?

 

[Hardwareman]

Mines been this way for years now without giving me overheating problems of any kind.

The best way would be a mechanical gauge.




Allen

 

[Jspafford]

Those stock guages are known to be pretty inaccurate. Mine never went past N in Normal. I got a mechanical guage and installed it. It runs 190 in the summer and as high as 210 in summer with air on sitting in traffic. This time of the year it runs 160 unless I am on the highway.

Stock guages suck.

Edit, the mechanical guage is extremely accurate, I can watch the temp get to 190, then see the thermostat open, it drops down immediatly, and then slowly comes back up.

 

[Kona]

Mine did that... I replaced the thermostat and lo and behold... it is now in the middle when hot!

 

[97ranger4x4]

Same here as Kona. A few years ago my buddy told me to just switch the thermostat and it warms up and stays right at Normal. Really easy to do and for an 8 dollar part its not like its a bad thing to do. You can also flush your coolant while your at it.