I have a BMW 316i 1990 (old shape).
The radiator bleed screw thread broke without being touched & I lost some coolant.
I've put a new official BMW Bleed screw back in. I've needed to top up the coolant twice since. The engine temperature gauge reading is normal & there is plenty of heat blowing from the cabin heater. There is no sign of any coolant leak now.
Does the need for me to top up the coolant again mean that there is air in the system & that it should be bled?
Secondly, if I needed to bleed the coolant - do I remove the bleed screw with a cold engine, let the engine heat up, put the cabin heater on max. heat & blower on, & then watch for air bubbles from the bleed screw?