BMW 650i Engine Coolant Temperature Sensor Replacement
Asked by B6M5W0 Jan 26, 2019 at 01:10 AM about the 2009 BMW 6 Series 650i Convertible RWD
Question type: Maintenance & Repair
I have a faulty engine coolant temperature sensor and have
purchased a new one so I can swap it out. I have seen
several videos where people simply pop the old one out, but
mine doesn't seem to cooperate, even with needle nose
pliers. My sensor also looks slightly different. Is there a
special tool I need to pop my old sensor out??
3 Answers
Hornet_2497 answered 5 years ago
Make sure they sold you the right sensor. Look and see if it's threaded like most and then you would thread it out with a wrench. If the engine is cold, you can do this without draining coolant. Just open the radiator cap to release pressure, then put the cap back on. That's a nice picture so it must be in an easy spot to reach. Good Luck.
Thanks for the reply Hornet. Are you saying to *twist* it out like a screw? The replacement sensor I bought was specifically listed as belonging to the 2009 650i, but it does not have any sort of screw-like "threads" as your answer would seem to suggest (see picture). Instead it has spring-action arms on both sides, like it should just pop in/out. But my current faulty sensor doesn't have those spring-action arms (or if it does, they are beneath some sort of black rubber covering ring (see original picture). Can you clarify your suggestion? Thanks!
Hornet_2497 answered 5 years ago
I can see on the new part there are no threads so it does not thread in. That silver ring must lock/unlock around the sensor. The "O" ring tells me it inserts into the cooling system at a fitting, but it must also have to be held in place by those spring action arms you mentioned. And they will not be on the new sensor because those arms are part of the car assembly. They must open up to receive the new part. Look it over and try to figure how it unlocks. Also lubricate the "O" ring with oil and turn it gently as it's inserted so it seats properly and won't leak. Then relock it with those spring action arms. Germans use this design on their VW cars. Sorry about the slow reply....busy fixing snow blowers too.