Operating Temperature 300SL -24 (R129)

[nerf]

Hello All.

My temp gauge needle has been sitting in the middle of the gauge for the short time ive owned my Mercedes 300SL. Ive just driven the car back from the garage where it had a general service and gearbox service. And the temp needle started rising very high (see attached). The antifreeze has been replaced so theres plenty of fluid in there. Does anyone have any suggestions why this might be happening? the garage has shut for the weekend so i cant call them until monday..

Cheers
Nerf

[r129sl]

Hmm. Stuck thermostat? Insufficient coolant? Air lock? I think it's unlikely to be a sender as the needle would be off the gauge.