Heat Gauge Jumping?

[stud4u2c17]

I have an 89 CRX HF, and when i start it and run it... it runs fine and starts fine now ... other then the oil leak out of the valve cover im fixing today... but... i was wondering why my heat gauge jumps... I will start it and it runs cool.... then when it starts to get up... it jumps up to all the way hott for like 20 sec. then it goes back down all the way to where it was... im not sure if it is really getting hot... or if its a faulty sensor? where is the sensor located so i can check it... thanks
TJ

 

[liquid00meth]

if it's jumping it's your sensor y0! engine temps don't change that quickly!



Edit: It's a given that you can check your coolant level, sorry. If your getting bubbles in the cooling system, that could expose to sensor to quick heat bursts.

 

[Frank_Li]

I'm not an expert but my car tends to do that also when I'm low on coolant.

 

[B16]

check your grounds and your alternator as well. electrical problems cause your gauges to act funny sometimes

 

[brian11to1]

If you are getting bubbles in your coolant/radiator that means the head gasket is most likely shot.

liquid00meth Edit:

It's a given that you can check your coolant level, sorry. If your getting bubbles in the cooling system, that could expose to sensor to quick heat bursts.