Removing rust from block’s water passages.

[Revenge]

What is the best way to remove rust paticles from the block’s water passages without totally refurbishing the block? I believe the word is called scaling. My concern is rust particles blocking the Exhaust Manifolds and Risers.

Thanks.

[Mischief Managed]

I have cleaned a lot of sediment out of my block with short duration shots of compressed air into the block drains while the engine is running on muffs. I open the drains, insert a rubber tipped air nozzle, blast a little air in the drain to stir things up and then pull the nozzle away to let some water/sediment drain out. It took more than 20 shots, per side, before the water drained clear the first time. I do it every year now, when I winterize, and only a little sediment comes out.

If you can get to some freeze plugs on the block, removing them will allow you to remove some sediment. With the manifolds off, they are pretty easy to get to.

[Bubba1235]

What is the best way to remove rust paticles from the block’s water passages without totally refurbishing the block? I believe the word is called scaling. My concern is rust particles blocking the Exhaust Manifolds and Risers.

Thanks.

How much effort do you want to put into it?

I've used a "home brew" to clean rust from iron for a lot of years that works well, but... it involves the use of chemicals.

Protective eye gear and clothing are MANDATORY!!!

In a 5 gallon bucket (plastic) of hot water (the hotter the better) add two cups of Lye. (Most hardware stores carry it.) Once completely mixed/disollved toss an old piece of zink in the bucket. An old anode works just fine. Allow it to sit for 15 minutes to disolve part of the Zinc.

Completely drain the engine block so it has no water in it.

With the thermostat housing removed (use a big funnel) and the block drains closed, pour the mixture into the engine block. Allow to set for 15 minutes. Drain the block (mix a LOT of water with the discharge.) Repeat as needed until you no longer get rust from the drains. To speed up the process, if the engine is still in the boat run it on muffs until its at operating temp before draining the block.

Note: After completing the flush, run LOTS of water through the engine.

The advantage of this over the use of commercial de-scalers is that it has no acid to attack the iron. The Zinc in the solution free bonds with the rust (Iron Oxcide) and breaks the oxygen link to the iron and the rust goes into solution to be drained away. It will not harm the iron at all.

By the way, this also works very well for exhaust manifolds if you put the solution into a flat container allowing you to lay the manifolds in it and submerse them in the solution. In fact it works very well on any rusted iron.

One more time WEAR PROTECTIVE GEAR. Lye can cause SEVER burns on the skin.

[wca_tim]

side note / comment:

Don't do this unless you're sure you don't have any aluminum water passages: ie aluminum intake, manifolds or risers, etc... at high ph aluminum will literally dissolve in pretty short order

[Bubba1235]

side note / comment:

Don't do this unless you're sure you don't have any aluminum water passages: ie aluminum intake, manifolds or risers, etc... at high ph aluminum will literally dissolve in pretty short order

You are 100% correct and I should have mentioned it. My bad...