It should be near the left rear corner, about 50mm inboard from the outer edge of the reservoir. It should be a six-eared plastic nut about 25mm in diameter, with a stud attached. The stud screws into a captive nut on the wheel housing. If the nut isn't there, is there a hole? The part number of the reservoir on our car is: 202 869 00 20 HPO. It is a 5.1 L reservoir. One other thing that you may have figured out already, disconnect the level switch wiring at the connector and slip the cable out of it's guide along the front side of the reservoir. If your car doesn't have the nut, maybe you just need to pull up on it.