Rusted clogged cooling lines in the block 5.7 merc alpha 1 gen 2

[jststrd1]

I was told my cooling lines are rusted and some are clogged. How can I clear these lines without removing the motor? Can I flush with acid?

 

[achris]

Hoses or engine block water jacket?

 

[jststrd1]

Water jacket not over heating on muffs actually runs good. But he replaced a head and noticed rust build up.

 

[itsathepete]

Take the hoses off and flush with water. Take the manifolds and risers off and flush them too. If they have a lot of scale and buildup you can soak them in a bucket of CLR or vinegar for a couple days. Flush the engine with water or radiator flush. Inspect the manifolds and risers for corrosion around the gasket surfaces.

 

[jststrd1]

I actually misunderstood the tech the blockages are in the block. He was telling me getting hotspots in the motor.

 

[Scott Danforth]

if the block is that rusted, it may not be long for the world

however, with that stated, here is what I have done.

with a large tub, a submersible sump pump (or a pond pump), vaporust or oxalic acid

pull the outdrive off
put tub under the stern of the boat and fill with vaporust or oxalic acid and water.
connect a hose from the sump pump to the inlet at the thermostat housing
remove the thermostat, install a restrictor plate (I used a thermostat that was wedged open)
let the pump run for about 10 hours, circulating vaporust or oxalic acid

it will loosen up much of the rust scale. however heavy rust means that the base iron in the block is disolving.

is this a salt water boat?

 

[jststrd1]

if the block is that rusted, it may not be long for the world

however, with that stated, here is what I have done.

with a large tub, a submersible sump pump (or a pond pump), vaporust or oxalic acid

pull the outdrive off
put tub under the stern of the boat and fill with vaporust or oxalic acid and water.
connect a hose from the sump pump to the inlet at the thermostat housing
remove the thermostat, install a restrictor plate (I used a thermostat that was wedged open)
let the pump run for about 10 hours, circulating vaporust or oxalic acid

it will loosen up much of the rust scale. however heavy rust means that the base iron in the block is disolving.

is this a salt water boat?

Yes it is a salt water boat. I will repower over winter. Trying to use it for season. It wasn't overheating on muffs and runs ok. Can I do this without removing drive it is an Alpha Drive so one hose for water supply.

 

[itsathepete]

Yes it is a salt water boat. I will repower over winter. Trying to use it for season. It wasn't overheating on muffs and runs ok. Can I do this without removing drive it is an Alpha Drive so one hose for water supply.

The drive is the first thing to be removed.

 

[Drcoffee]

this stuff works great for disolving rust and can be reused rather than disposed of.

 

[jststrd1]

Take the hoses off and flush with water. Take the manifolds and risers off and flush them too. If they have a lot of scale and buildup you can soak them in a bucket of CLR or vinegar for a couple days. Flush the engine with water or radiator flush. Inspect the manifolds and risers for corrosion around the gasket surfaces.

Manifolds and risers are clear it is just the block. The previous owner put new manifold and risers on he bought this engine used.

 

[Bondo]

Manifolds and risers are clear it is just the block. The previous owner put new manifold and risers on he bought this engine used.

Ayuh,..... Welcome Aboard,.... There's a drain plug, down low, mid to aft of center, near where the block meets the oil pan,....
One each side,....
Pull those plugs, 'n start diggin' there,....
I use a 4" ssteel deck screw that lives on my intake manifold, so it's there for winterizin' the motor,....

 

[achris]

Can I do this without removing drive it is an Alpha Drive so one hose for water supply.

Pulling the drive is a 5 minute job. Putting it back, 3 minutes. (Have a look at my videos)

Chris...