Just noticed that my engine coolant gauge isn't working quite right. This past week it started reading low...almost at lowest point on gauge....then will swing up past quarter point...then drop down again. When I check coolant temp using digital readout, it's bouncing around by about 10 deg rapidly. Never did that before. Engine oil temp and tranny temp are below midpoint and read consistently. Figure it might be the coolant sensor but I have no experience troubleshooting this type of issue. Thoughts? Thank you.

 

My 09 did the same thing , all at once it started bouncing up and down . Took it in , it was the thermo stat and sensor. work was covered under the max care ext. warranty ..
Covered rent car and paid 100.00 deductable

 

Thanks!