I'm not familiar with your car, but on my '82 380SL and '79450SL the spray nozzle has two tabs that must be squeezed together to remove the nozzle. New nozzles aren't too expensive, I'd order a couple and have them on hand before attempting to remove the old ones. Performance Products has them listed, as I recall around $10 each. I broke mine when I removed them as the plastic was brittle.

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Richard Wooldridge
'01 ML320
'82 300D 4.3L V6/T700R4 conversion
'82 380SL, '86 560SL engine/trans. installed
'79 450SL, digital servo update
'75 280C