Bleeding a cooling system with bleed screws

[MarkA67]

I can find plenty of videos and guides online that shows you how to bleed systems without bleed screws, but finding ones on how to bleed systems with bleed screws are very rare. When you do find them, they usually have contradicting information!

So, what is the correct way to bleed a cooling system with bleed screws? Some guides say to remove the bleed screw fully, others say don't. Some say to open all bleed screws at the same time, some say to do it one by one. What is the actual correct way to do it?

[V8RX7]

Very much depends on the car.

However there is no need to remove them - particularly bearing in mind you will have boiling water squirting out of them !

Generally you loosen them once when filling up, then close, run up to temp, then open and close once a stream of water comes out.

[Krikkit]

As noted it varies completely by system. I've never heard of one where you pull the screws while hot though. As a general rule you start by opening them all, and closing them in sequence as the coolant starts running from them while you fill.

Good example is a 106/Saxo with the TU engine - start by the bulkhead with the heater, then the radiator, then the thermostat housing as it's the highest.