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Temperature gauge on dashboard moves very little

1996 Mazda Protege, 125,000 miles. Temperature gauge on dashboard moves very little. Q:

  1. Do I need to get this checked out, ie, if not what would happen? (I have had car in recently for other problems but no one n the shop mentioned it, even though they have had the car out for a drve)

  2. Approximate cost to replace/repair. I live in Midwest.

Thankyou.

Perhaps first see if the coolant temperature gets to the proper level. Not sure how they have a Mazda wired but there are often at least two sensors: one for the computer and another for the dash. It could be that your dash gauge gets its temperature from the computer, in which case you only have one.
Regardless, you want to see what the actual temperature is.
Do your radiator fans come on and stay on, even with the AC off, by chance?

Autozone or pepboys can check engine codes for free and they may be able to read what the computer thinks the coolant temperature is using that same method. Most more advanced scanners can do that.

If the engine’s coolant doesn’t get to proper temperature, the problem may be a stuck open thermostat.
While it isn’t a catastrophic failure, it will cause you engine to not run properly and efficiently. In colder climates, it will cause the engine a long time to heat up and in winter may cause you not to have heat in the cabin for more than what’s normal.

It the coolant temperature is indeed correct, it could be that the sensor used to feed the gauge is broken or somehow disconnected. Obviously, that would just be a readout problem, an annoyance.

So it’s showing cold all the time? It’s almost certan to be a bad thermostat, failed in the open position. Just changing the stat is no big deal, but you (or your independent, owner operated, shop of choice) may want to flush the cooling system and change the coolant too. If the coolant has not been changed for three years or more, I’d suggest doing it. Expect to spend $100 or so.

I would strongly reccomend haven the car looked at becouse as other people have said this can cause other problems left in thios state of repair woarse case overheated engine with a blown head gasket and a warped head or it can be a simple as a bad t-stat and waste a ton of fuel.