replacing coolant on yanmar R25

[nzfisher]

So I am trying to keep up with the maintenance on my boat. I don't want to remove the heat exchanger if there is some other way to replace the coolant for the engine. Has anyone tried to suck it out with a pump? If so, how did you do it? Step by step for the complete idiot would be nice. I did do a search first. Most info about coolant relates to overheating and what type of coolant to use.

Thanks!

 

[knotflying]

I have a 4BY2 on my R-27. There is a petcock on the side. I hooked a small pump up and sucked it out. You will not get all of the antifreeze out by this method. However, my plan is to do this every year and I would say you will be putting in enough new antifreeze to keep the inhibitors and lubricants fresh.

Mike Rizzo

 

[PhilR]

If you have a cooling system drain/ petcock low enough to drain most of the antifreeze, you can remove the hull drain plug with the boat on the trailer, place a container on the ground under the hull and drain the antifreeze out thru the bilge.

Phil