M20 Bleeding the cooling system

[Vinu Chandrakumar 6]

Hey guys, 

So i have just put in a new radiator in my car, and will be attempting to bleed the cooling system for the first time. Firstly should I be draining the coolant in the engine, when i took out the old radiator, I only drained the coolant by removing the radiator drain plug, should I remove the bolt that is on the engine block too, before bleeding the cooling system? 

And what is the best way to bleed the system? Any help will be much appreciated.

Cheers,

Vinu 

[Juzzo 0]

There is a bleed screw directly on top of the thermostat housing. Open that while the car is running with an 8mm spanner (just loose not all the way out) and it should fizz while air comes out then after a while just coolant. Retighten then test to see if it runs to temperature ok. 

There may be another bleed screw somewhere but this is the only one I know. I hope that helps.

J.

[hotwire 352]

As above - loosen the bleed screw.

Yes drain the whole system, if it is dirty then flush the engine until clean. Add a couple of litres of fresh antifreeze, turn the heater control to hot. I find it best to about 2/3 fill the system, run until the thermostat opens & slowly top up the system and wait till only water comes out the valve, Secure & top up the reservior. Drive & confirm temp is ok. Recheck level when cold.

They can be a bitch to bleed if not done correctly.