I replaced mine in August. The access to the coolant level float is improved by removing the top section of the air filter box. Snap ring piers are necessary to remove the snap ring that holds the sensor to the reservoir. Don't remember if an 'O' ring is involved, probably is, so best to inquire when ordering the sensor. With 10% MBCA discount, the sensor cost about $30 if I remember correctly.
regards,
Mark