Reason I ask is that today I changed the coolant expansion tank on my '89 240 and didn't really bleed the cooling system properly. The FAQ says you should bleed it when you change hoses or the thermostat or when doing a cooling flush. It says to bleed by loosening the thermostat housing. I didn't do any of that. In my tank swap, I lost approx. 1.3 qts of antifreeze but replaced this same amount. Filled the the tank at the MAX level and then drove six miles to run an errand, enough time for the car to reach optimal temperature. I got home, let the car cool for about an hour and then checked coolant level. It was the same but maybe a mm or two above max (due to hot coolant). I then unscrewed cap to release any trapped air (that's my way of bleeding). Later on (after I remembered the bleeding procedure) I started the car, let it idle a bit, and before I could let the temp get at the 9 'o clock position, I turned on max heat and felt hot air at the vents. Am I good to go? I know I didn't do this last part on the drive way and after I had replaced fresh coolant. The fact that I didn't notice a drop in coolant level after driving around, does that mean there was no air bubble to begin with? Thanks all!