how does one flush out rust from block?

[1975oday22]

I took the thermostat cover off and found the thermostat to be rusted . as far as i can tell that rust has gotten into the block. i will be cleaning the theromstat housing and blowing it out to make sure of no debris. how should i clean out the block ? alot of rust came out the drain when i drained it but i want to fully flush it out. no water in oil so i know that there is no problems there. right now i have the lower part of the thermostat housing in vinegar. going to leave it sit for the night. then put in the upper portion.

 

[Scott Danforth]

All marine blocks using raw water cooling have rust in them

However I'd you want to flush it. Mix up some oxalic acid and fill the water jacket up.

Let sit for 3 days.

Flush with water

Repeat

 

[1975oday22]

any other product that is actually safe for the environment? ie wildlife and other animals..

 

[rallyart]

Well, you could change your engine to a closed cooling system with a heat exchanger. But if you use your boat in a fresh water environment the block is not going to rust our from the raw water cooling system.
I think the suggested antirust treatment was to use on shore and would not, therefore, have any affect on the water or marine environment.

 

[jimmbo]

Oxalic Acid isn't Environmentally or Animal unfriendly. It is what makes Rhubarb Leaves Toxic for Humans, but I've seen other Animals eat them. Of course I didn't follow them around, so maybe it did kill them

 

[1975oday22]

Well, you could change your engine to a closed cooling system with a heat exchanger. But if you use your boat in a fresh water environment the block is not going to rust our from the raw water cooling system.
I think the suggested antirust treatment was to use on shore and would not, therefore, have any affect on the water or marine environment.

hence i wont use it as it is toxic . not safe for marine = not safe for domestic pets. thanks for clearing this aspect of it up for me.

 

[1975oday22]

ok , so the verdict is, i took my drill and used brass wire spinner. cleaned the thermo casing right up, made 2 of 3 gaskets. and now im done for the night. i will run water through the intake to clean the rest of the rust out. now a question about the riser. should i be taking this off to clean the holes out or do you think the water will be sufficient in going through? and if i do take the riser off, can i use red high temp rv gasket instead of replacing the existing gasket?

 

[stresspoint]

i read on another forum you can flush with white vinegar.

 

[tpenfield]

This stuff . . .

 

[briangcc]

Another option....Pull the engine, disassemble, take it to an engine rebuilder, and let them dip it for you.

Reassemble with new gaskets/rings/bearings, realign, go boating.

 

[Scott06]

ok , so the verdict is, i took my drill and used brass wire spinner. cleaned the thermo casing right up, made 2 of 3 gaskets. and now im done for the night. i will run water through the intake to clean the rest of the rust out. now a question about the riser. should i be taking this off to clean the holes out or do you think the water will be sufficient in going through? and if i do take the riser off, can i use red high temp rv gasket instead of replacing the existing gasket?

get a proper riser gasket as this is a point where if it leaks water will drain back into cylinders

 

[Lou C]

can these oxalic acid treatments damage head and intake gaskets?

 

[mike_i]

We use oxalic acid in beekeeping, kills mites but does not harm bees.

 

[1975oday22]

Another option....Pull the engine, disassemble, take it to an engine rebuilder, and let them dip it for you.

Reassemble with new gaskets/rings/bearings, realign, go boating.

thats not an option. but thanks for that....

 

[airshot]

Everything you do in life will have a negative effect on something...so choose which one you do/ don't want to effect...many if these products are fine if they are handled/ disposed of properly !!

 

[1975oday22]

Everything you do in life will have a negative effect on something...so choose which one you do/ don't want to effect...many if these products are fine if they are handled/ disposed of properly !!

as with everything, however once i am ready to take it out to the driveway , i will then use my pressure washer and some vineger and flush it out that way. thanks for the advice and helpfull guidance. cheers

 

[tpenfield]

IIRC, baking soda neutralizes the oxalic acid. I flushed my 7.4L engines with it about 7-8 years ago to purge some internal rust.

 

[Horigan]

IIRC, baking soda neutralizes the oxalic acid. I flushed my 7.4L engines with it about 7-8 years ago to purge some internal rust.

This! Anytime I use an acid product, I buy a bunch of baking soda, neutralize it, and pour it down the drain.

 

[H20Rat]

hence i wont use it as it is toxic . not safe for marine = not safe for domestic pets. thanks for clearing this aspect of it up for me.

You know the exhaust from your engine is highly toxic? That is injected directly into the water you are boating in...

Its all about the dose. Almost everything is toxic at a certain level, even a fair amount of everyday food we eat. (tomatos and potatoes in particular) Dilute the acid enough and it is a non-event. In reality, if you dumped it on the pavement and flushed it with a hose, it is going to be well below a toxic level, especially if you mix in some baking soda.

 

[1975oday22]

well here is the theromstat body. the gasket you see is is the one i made from gasket maker that i had from a friend of mine. not sure if i have a big enough piece to do the riser but will soon see. as for the rust in the water jacket i will flush it out once i get the boat outside with my pressure washer.