Before I attempt to replace any bits I'd appreciate the opinions of those who are wiser than I!
Since I started driving this car (October) I noticed that the temperature gauge needle didn't sit halfway but at around 4 o'clock, only going to 3 o'clock when the car wasn't moving. I put this down to the lower outside temperature. Fuel economy was 23.3.
Last night the Lambda light came on. The car seemed to drive fine but fuel economy dropped 2mpg, and when I got home and switched off the engine, the radiator fan ran for several minutes. The temperature gauge had also dropped very low.
Turned the ignition on this morning and the fan came on at once. Started the engine, the fan speed increased, then shut off after 15 seconds. It hasn't come on since. I noticed the engine idled higher than normal, though not rough.
OBD2 scan pulled one code: "P0116 - Engine Coolant Temperature Circuit Range/Performance Problem"
I cleared the code, Lambda light disappeared, engine idles at 880 and no fan yet. Antifreeze in expansion tank looks clean and oil hasn't turned to chocolate milk, so hopefully not a blown head gasket!
So my main suspect is the thermostat and its temperature sensor. But if anyone has a deeper insight please chime in.
Lambda sensor was changed in 2010 by the way, and for what it's worth the car (a 1998 C70 T5 GT auto, Motronics 4.4) also has a RICA ECU 310 upgrade.
Thanks in advance!
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