316 cooling riddle

[wokingsaab]

Fellas

My E30 316 overheated on my way from work. It's an 8 mile journey with 3/4 stops and doing about 50/60mph on most parts.

I noticed the overheating after I parked at home and steam was rising from the bottom. Opened the bonnet and coolant was exacaping from the header tank.

I let the car cool down, added some coolant and it immediately shot up to the red. I turned on the interior heating and was only getting cold air.

So I read the e30 cooling system wiki and decided to first bleed the system. After a lot of bubbling and addition of coolant, voila! interior heater is back on, and after a few revs, temp gauge goes up to operating and stays there. I took the car for a 10 minute drive doing 50/60 and there the gauge remained. So all seems to have sorted.

My question is this: why did the system get so airlocked in the first place? Do I need to replace some service items to ensure this does not happen again? I use the e30 for some lengthy journeys and would hate for it to pack up on me. The rad, thermostat, waterpump and belts were replaced 11,000 miles ago during an engine rebuild.

thanks for your help.

Thoko