No air bubble. I've had those before so pretty familiar with them. It may be the coolant temp sensor, but the interwebs tells me on my make and model its more likely the thermostat stuck open. The computer code isn't matching the dash readout (computer code is for engine temp lower than it should be based on its algorithm), and the car never reaches proper operating temp unless its hot out. The thermostat may have been stuck open for awhile, and never had any symptoms until summer was over because the problem started on the first cold morning we drove it.
If the temp sensor isn't too much $ I might just replace them both at the same time along with a coolant flush, in which case I'll never know what the culprit is. The sensor is a bit trickier to replace than the thermostat, so I have to gauge my motivation level along with the price. There is a third common cause of the error, which is a problem with the cooling fans being overactive.
If the temp sensor isn't too much $ I might just replace them both at the same time along with a coolant flush, in which case I'll never know what the culprit is. The sensor is a bit trickier to replace than the thermostat, so I have to gauge my motivation level along with the price. There is a third common cause of the error, which is a problem with the cooling fans being overactive.