How reliable is the digital temp gauge in '86 GL-10 EA82T?

[Unovis]

I have a '86 GL-10 SW 4WD with an EA82T and digital dash display.

 

I've always wondered about the reliability of the digital temp gauge... It seems to show temp spikes fairly often. Granted, as far as  know, the temp sensor is original so that may be a problem. 

 

Also, it seems like it'll show a temp spike when I turn the heat on- Seems like the opposite should happen. Does running the heat somehow activate something in the A/C causing the motor to run hotter? Dumb question, but Subarus can be weird when you're only used to working on old '60s Fords!

 

Thanks- R.

 

 

[jono]

I have learnt that with these old subes, the gauges non digital will tell you what the sender tells them had one sender that never went above quarter , so I thought everyone else complaining about overheating EA82s had other problems

 

you say turn the heat on and see a spike, but AC is cooling and compressor and condensor in front of radiator would increase engine load but would not cause an immediate spike in temp. An electrical thing in the engine block to body earthing , naaaa, more like an earthing change in your dash. Is there a spike in any other read outs at the time.. did you turn up the heat on a dial or slide adjuster? Or did you turn the internal blower fan on ?

 

60's Fords do rule for simplicity - never needed anything smaller than 1?2" drive sockets until I ventured to Japanese cars With one exception to remove a C pillar trim nut accessed from within the boot (trunk)

[l75eya]

I've heard they are not to be trusted much. That being said, mine seems to be on point with where it will get to when the fan kicks on, which is the middle of the gauge. The fan always kicks off after about five minutes of sitting at the 3rd segment. So it is at least consistent, on my car anyway.

[Flowmastered87GL]

Don't trust them at all.  I had one that would be 3 bars up, but my analog gauge would be indicating overheating.  My 86 Gl-10 Turbo.... I can't even remember how many times we overheated that damn thing.

[calmblin_gl10]

i have the digi display and i must agree that it is inconsistent and also some other wonky nonsense with the fuel indicator going up instead of down. ive done some groundwork wherever i can find it and it has helped a little( it hasnt just gone to the roof for no reason or will jump around based on the load to the system)  but i still have bars showing up or going away where they shouldnt. (if someone would clarify the ground from the display to the body or engine i would appreciate it)  i intend on installing gauges for the battery the engine temp. and oil temp. because i absolutely dont trust electronics that have failures just due to age. there is virtually no rust to be found throught the body frame or engine and very low millage. so im fortunate compared to really only having digital display issues. though its unnerving to think it could all possibly go up in smoke without it actually warning you. generally if i feel the engine is trying to tone it back a little or even resist throttle. i find a nice little spot to pull off or just drive a little slower. it usually catches up. 

[nipper]

If your alternator is wonky it will affect the digi gauge reading.

[scoobiedubie]

They are not accurate when the heater is running.

[nipper]

They are not accurate when the heater is running.

 

Or the engine is running