Replacing coolant - Can't open bleed valve

[geekeasy]

I have Marine Power 5.7l in my Silverton 312.

I had to dump all of the coolant on my engine while doing some work on the boat and I'm trying to re-add coolant.

Unfortunately, there is terrible access to the bleed valve, and despite my best efforts I cannot get it to open.

Is there any way to purge the system without opening this? Can I just run it gently and keep adding cooling as the system purges itself?

Thanks for any help!

 

[makomark]

I'd suggest filling the HX, running the engine until the T-stat opens and then shutting it off...and then cool until the T-stat closes...run thru a few cycles and the vast majority of the air in the cooling system should be purged. If you have the overflow (degas) bottle and the cap is in good shape, you can monitor the level there...

You can expedite the purge process by applying a vacuum to the coolant side of the HX...

 

[geekeasy]

I'd suggest filling the HX, running the engine until the T-stat opens and then shutting it off...and then cool until the T-stat closes...run thru a few cycles and the vast majority of the air in the cooling system should be purged. If you have the overflow (degas) bottle and the cap is in good shape, you can monitor the level there...

You can expedite the purge process by applying a vacuum to the coolant side of the HX...

I just want to confirm that all of the air will gradually work it's way out.

If this engine keeps overheating, I can look to another cause and it won't just be because some air is trapped in the cooling system because I couldn't open this bleed valve.

 

[makomark]

as long as the fill neck on the HX is the highest point in the system, then yes, the air will eventually make it to the HX...

you can also tell that the air is gone when the coolant level stays constant after a run...in other words, check it cold, run the engine and let it sit until cold again and then check the coolant level...if it hasn't gone down then the air is gone...