Flushing the coolant

[Cloggy Saint]

Is it simply a case of removing the drain plug on the block and putting a hose over the stub on the inlet side, or is there more to it than that? Thanks.

[Brianmoooore]

If you drain a M20 at the block plug and at the radiator, then the only coolant left in the system is that in the heater.
Personally, I like to keep the skin on my knuckles intact, so usually leave the block drain well alone, and just drain the radiator, then flush the rest of the system with clean water.
Refill with the correct total amount of neat antifreeze, and top up with clean water, and the job's done.

[Cloggy Saint]

The engine's on a pallet and the block plug is already out, so no skin loss issues. So it's as I outlined in the first post?

[Brianmoooore]

Hell of a lot easier on a pallet! Depending on how fussy previous owners have been about coolant changes and concentration, there mayt be some sludge to flush out.

[daimlerman]

What are your plans for this engine?

[Cloggy Saint]

The plan was to freshen it up and have it fitted about 18 months ago. The reality is freshen it up (done) and then look at it on it's pallet every now and then and come up with excuses not to fit it

[Cloggy Saint]

Digging this up again. To flush the block do I need to attach a hose to the stub at the back of the block or the one on the side?

[pacerpete]

As it is on a pallet, I would attach the hose to the pipe at the back of the head, it is the highest on the engine and gives you a better shot at flushing all the crap out. Either way, it does not matter too much which orifice you use (must resist !) as long as you end up with clean water coming out.

[Cloggy Saint]

Ok, thanks, and thanks also for resisting!