I will be replacing mine soon, and that will be sensor replacement number two (last replacement was four years ago). I have only replaced the coolant reservoir tank once, and that was due to a loss of copious amount of coolant showing up in pools underneath the tank, not the radiator or pump.

I've noticed that some replacement parts have shown up lately that are cheaper than OEM...but the tradeoff is that the quality is sometimes not on par with OEM, and thus, longevity is compromised.

If you aren't seeing a noticeable loss of coolant in your reservoir, then you don't have a leak, you have a bad sensor.

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car