2000 c70 problematic temperature gauge

RickyRootle · Post by **RickyRootle** » 29 Aug 2015, 20:46

the temperature gauge reads normal at idle once car is at operating temperature, but whenever accelerating or just depressing the gas pedal (if its in park) the needle goes all way to zero. Once at highway speed it will sometimes gradually creep back to normal, but drops back to zero when starting back from a stoplight etc. it seems to be directly connected with accelerating the engine speed Coolant temp sensor has been changed ( the one in the thermostat shroud) am i missing finding another sensor somewhere? took my car to a supposed volvo specialist garage just to be told they have no clue why it does that $$$ thank you for your business. im new to the forum and volvo thing so patience w me please as i learn

I just want my car to be "right"

Post by **Ozark Lee** » 29 Aug 2015, 21:58

That is the only temp sensor that feeds the instrument cluster. Did the thermostat get changed along with the ECT sensor? Was the replacement sensor OEM or an aftermarket? The car is pretty picky about the ECT sensor and most of the aftermarket sensors are trouble. If the thermostat didn't get changed that is where I would start.

...Lee

RickyRootle · Post by **RickyRootle** » 30 Aug 2015, 10:05

Hi lee. It was an aftermarket sensor from ipd. The tstat has been changed ...guess I need to start over with an oem sensor. Ill check back in if that doesn't do the trick. Thanks.... ricky

Post by **oragex** » 30 Aug 2015, 10:51

The two things I see happening when you rev the engine is the water pump speeding up - the coolant flow speeds up, and the coolant temp going up a little. For the first I would make sure there is no air trapped in the coolant and that the thermostat air bleed nipple is in the right position (usually at the top of the t-stat). For the second, if the sensor registers a temp increase as a temp decrease, it might be faulty, as mentioned.