JCtx
Member
Air doesn't enter the system if you keep the reservoir above the 'MIN' line. The issue we're talking about here is air EXITING the system, hence the need to replenish the reservoir. It's basically impossible to avoid having air in the system when you fill it up with coolant from the factory, so a new vehicle owner needs to always pay attention to that when car is new. The cooling system stabilizes eventually, but it takes many full cold-hot-cold cycles for that to happen. But after the initial purge, the difference should be minimal.
