Please help, Freshwater System Flush

[Chris Craft Johnny]

My antifreeze solution is looking really nasty and I want to flush and clean the freshwater cooling system and replace with a new 50/50 blend on my 1986 350 hp big block Crusaders. Could someone please give me the proper procedure for doing this? Thanks

 

[makomark]

You do it like you would any other engine...simplest way is to not modify the plumbing...drain the system by removing the two block plugs and the big hose feeding the circulating pump (details in the owner's manual)...flush with a good chemical solution...drain again....flush with water...drain again...refill with coolant.

I'd suggest using 100% coolant out of the jug as you won't be able to drain things completely...that way, you can adjust the concentration to your local environment...using 50/50 premixed will yield you with less than 50% coolant in the sytem...

 

[RicardoMarine]

I agree with Mark if you drain according to how he suggested, and if you flush with a chemical solution, and neutralize afterwards.

The side engine drain ports and the lower circ pump suction hose should do the trick.

I'd be surprised if any substantial amount of residual flushing water remained.


Pick yourself up some coolant PH balance test strips, so that you can keep an eye on your coolant in the future.


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[Chris Craft Johnny]

Thanks guys, Mark I sent an answer to your PM.