Hot Running '71 Convertible

I have a '71 Super Beetle convertible that keeps the oil lamp glowing when idling. Engine seems to be running hot, especially with the top down in hot weather.

Any suggestions?

Is all the cooling tin in place (check against a repair manual)? Is there any debris in the cooling fan behind the generator? Is the rubber air seal around the engine intact? What weight oil are you using? If you grab the crankshaft pulley at the fan belt how far does it move if you push & pull it forward & backward.