Bleeding cooling system

[B4A]

I just changed the coolant on my Yanmar 3YM30AE.

Question: How do I bleed the cooling system to make sure there are no pockets of air?

TIA

[Emmalina]

you dont have to

[sailormed]

Check for a bleeding cap/valve/... on the hoses going to and return from the water heater. It is mostly here that air accumulates in the cooling system.

[capt jgw]

Unless you have an engine heated water heater mounted higher than the engine. If so there should be a fill cap or header tank at the water heater. Fill the system from there and run for a bit with the cap off topping up if necessary. You need to vent any air from the highest point in the system which in this case is the water heater. If no water heater then the header tank on the engine should be the highest point and all you have to do is fill it up, run it for a bit and top up if necessary.
On edit I see Sailormed beat me to it.

[Cheechako]

-If you want to bleed the engine entirely for storage etc be sure to do it hot. That way the thermostat is open.
-Ensuring no air pockets is similar, you need to get the thermostat open somehow. If there is air around the thermostat, the engine may overheat while not opening the thermostat. The solution is to pour hot water in where it can get to the thermostat.
Dont ask how I know this!
-Generally, the thermostat issue aside, you need to open the highest point in the hoses (like a water heater hose) to ensure the air is out.

[Shrew]

My engine is higher than my water heater and the water heater is tied into the coolant loop. I remove the cap on the coolant reservoir (not the expansion tank) and fill it with coolant, leaving just a little bit of headroom. Then start the engine and keep topping it off. Even when it looks full, I still run it for a while because it may burp a bit slowly toward the end.

Then pour some in the expansion tank. I usually fill to the warm level. check levels after the first real run under load.

[B4A]

Thank you guys!

I don't have any bleeding cap/valve. My water heater is at the same level as the engine.

I know the radiator caps are a real piece of engineering and they work as both pressure and vacuum valves. Will the air bubble also be able to escape this route?