Tempeture Gauge acting funny

[OttoFalcon]

Hello!

I own a 97 GS and when i bought it it was in bad shape oil leaking everywhere and bad idle, fixed all that now the car runs like a champ, a month ago the temp gauge starded spiking and moving relative to the rpm gauge, if i acelarated the gauge would move down and if the car sat @ idle it would be at the normal operating temp. but now it just doesn't read the car starts to warm up and it's working fine but when it reaches "normal" temp it starts to spike or not work at all, so i changed the coolant sensor, thermostat and cluster "silver faced cluster looks a lot better" and still same problem, does coolant type have anything to do with this issue? could their be air in the line? is their a short?

and also my speedo is acting up, the cel says it's the speed sensor but! somedays it works fine no problems but others it's a whole diferent story. thanks for the help!

 

[ThomasGSX]

its a possibility that your system is air-locked, basically a bubble of air is trapped in the cooling system, first thing I would try is parking your car on a uphill area, and run it for a while with the radiator cap off and keep topping the fluid off, if you do this and the problem persists, it could be something else such as your water pump or the gauge it self even.

 

[mazda-man]

With the radiator cap off and the car off you can fill it up and then squeeze the bottom radiator hose which will move the coolant around the engine and get out the air if its trapped. Some cars have bleeder screws on top of the thermostat housing but I don't think the 420a's do. Coolant type should not make the gauge bounce around. Also make sure the connector that snaps on the sensor is clean and doesn't have any corrosion. If it does use a little electric contact cleaner and a piece of sandpaper to clean it.

 

[bigbird]

When I had a dead cylinder in my MR2 I had this problem. The cooling system is designed to cool all four cylinders. If the RPM goes up the water pump moves enough water to cool 4 cylinders and there are only 3 producing heat.

If this were the case you would probably notice a rough idle and low power.

It could also be a bad ground for the instrument cluster.

 

[knochgoon24]

Get your alternator checked. The changing voltage can really mess with the gauge reading.