Engine flushing

After taking out the 2 block plugs, which are on either side of the block at the rear end, I can see that there is good evidence of brown sludge which is and has gone hard and crusty. I have heard that most of the sludge is deposited around the liners at the other end of the block.
I am thinking about flushing the coolant system with an additive to dislodge these old deposits.
Any advise on what to use or not use?
Searched Google and found :
Starbrite engine descaler
Wynn's Radiator Flush
Some Americans have used "washing soda" successfully
Oxalic acid has great rust removal properties (according to wiki too) and often sold as "Barkeeper's Friend"
& with pictures..... http://www.jalopyjournal.com/forum/threads/tech-using-oxalic-acid-to-remove-rust.248198/
vinegar (probably white wine vinegar).
Also i read that some folk have used IR temp reader to see if block temperatures are unifom.

Hi Simon,

Are you planning to take your engine apart ? Surely those wonderful chemicals that can remove rust will also affect all the seals gaskets hoses etc they come in contact with if used on your car, might do more harm than good ? I dunno, just a thought...

Ced

Not wishing to dismantle the engine, just wishing to flush it.
When you removed your heads.....was there a lot of rusty sludge at in the block at the front end around the liners etc?

I dismantled the whole engine and cleaned it. The water that came out was very orange and there was some internal rust in the block and liners but not a massive amount. All cleaned fairly easily but again the engine was in bits so easy access...

I have flushed the orange water out, with hose pipe through the block plugs, but there is some solids in the block.
After a 1500 mile drive, and tour of France, the water is still clean, so I guess these solids will stay that way.
Found this too, but never a fan of American products.
https://www.evaporust.com/cooling-system-cleaner
how would one know if GTA has magnesium parts in cooling system?

Hi Simon
I would not put any form of chemical flush in your engine, you will be asking for problems especially as the aluminium around the liner seats is now a very prone area. The bulk of the build up will be around the liners at the front of the engine. When I rebuilt my engine it was so hard it was like concrete and bone dry, so no chemical would get through that anyway.

Hmmm, the hardness is what I was fearing.
The little bit by the drain plug was hard and crispy.
I think I will leave be.

Anyone any experience of Evans Waterless coolant yet?
Might surf Piston Heads, I suspect someone there may have tried it.

A wise decision, put in type D coolant if you don't have it antifreeze that suitable for all metals but remember always mix it with distilled water do not use tap water.