Flushing out closed cooled 454s

[footloose]

Hi folks - been awhile.
I am looking to flush out Merc 454s with closed cooling as the antifreeze is looking sketchy. Is there something I can safely run through the engine or in it while it runs to descale and remove as much crap as possible?

I did searches and hear everything from vinegar and calcium build up remover stuff to other strange concoctions.

I know how to take apart the heat exchangers and clean them but not sure about the block itself.

Thanks

Olivier

 

[boatbum]

Heat exchangers can be treated with phosphoric just pull the zincs. I disconnect the hoses from the inlet and outlet and cycle a mix through with a small bilge pump. I would not run this mix through the risers. Well, you can't because it will go over the side anyway. Our engines have an inlet at the transmission cooler from the strainer. So this goes to the bilge pump. The main heat exchanger is last in the circuit before it goes to the shower head downstream of the turbo so that gets disconnected and sent to the bucket.
I pull the impeller and put the cover on then run the acid mix through until is stops bubbling. It cleans everything up real good. Flush it out, install new zincs, and we're good to go.
On the closed loop I'd drain them and fill with distilled water and run them a while. Then go after the "brew" for the closed loop.

 

[Bruce Herrington]

I used barnacle buster; easy, simple process..