hello, first time poster, long time do it yourselfer.
i have a 2006 XC90 with the turbo inline 5. this car has been both a blessing and a curse on me, with the latter being why i'm posting.
recently my SO and i were driving to a family get together (30+ miles away and all highway) when we noticed it felt as if the car were getting colder. well there was no time to stop and it was -8 degrees F out. driving back home that night, we watched the temp on the gauge slowly decline as well as it blowing colder and colder air. finally temp reaches down to zero and the radiator fans are howling. fast forward the next day, i go to the local oreilly auto store and get a thermostat for it. as i fight my way into pulling the old therm out, i realized the new and old therm are completely different. lots of arguing and research later, i find out that i cant buy "just the thermostat" for this model, instead, i have to replace the ENTIRE THERMOSTAT HOUSING FOR $150.... had to pull the power steering pump and belt to access the bottom half of the housing, get the new one all situated, coolant burped, low and behold it blows hot! mid celebration dance, i notice that the temp gauge is still at zero. (dbgfqouwecnggoqgo) oh well, car blows hot, wife's happy right? next day get a call that the car is telling her it's low on coolant and she must shut down engine. okay, i get to the car added about 12 oz to it, fired up and has been blowing fire ever since. a few small quirks i've noticed since doing this was sometimes the engine will start hard and run like crap for a minute or two before running smooth. i just bought one of those volvo/saab dealership readers and ran it today. it gave me a PO116 code, and said that that sensor also will help the ECU regulate fuel/air mixture, spark, etc. pretty important, especially when it's been running goofy since the swap. my question is; do you think that the sensor i got on the new housing (it came as a whole set, new sensor and all) is faulty and that's why my gauge doesn't work either, or is there another temp sensor located somewhere on this engine? thanks for taking the time to read this book!