To chemically clean out engine raw water passages

[DaveS]

This is a subject which I'm sure has been done to death on TOP, but I struggle to find old threads there. In short, I'm looking for recommendations for something to put into my engine block to clean out scaling. Any advice, particularly from someone who has actually done it, most welcome.

[Aja]

Dave

Seems to be a current arguement going on here: http://www.ybw.com/forums/showthread.ph ... ing-Engine

Regards
Donald

[ash]

I did my old MD6A at the beginning of my first season using brick cleaner from B&Q. The alkaline version didn't work. Needs to be the acid one. Works better with a bit of heat in the block. I removed the thermostat first so that it wouldn't be damaged. I set up a system with header tank and collection bucket so that I could back flush the block. If I did it again then I would buy a cheap pump and set up a circulation system. Take all the usual precautions with acid. I thought that it was worthwhile. Ash

[Booby Trapper]

Used Brick acid on my old Yanmar YSB. no adverse effects (that I know of). Pourded it in and it fizzed for a while, flushed it out.
Don't fill it right up as it does fizz a lot and can bubble over.

[DaveS]

So the latest TOP discussion favours Fernox radiator flush, with some variations of ideas as to whether or how to continuously flush. Two here have used acid brick cleaner, either as continuous flush or "let it fester and fizz". Everyone agrees that it needs to be hot, and removing the thermostat is probably a wise precaution, as is leaving some space to avoid overflowing. If using acid, presumably removing the zinc anode is also worth doing?

[sahona]

Yep, remove the anode and anything else alloy-ish. The brick cleaner I use doesn't need heat but it may make the action more vigorous ( as my old chemistry teacher would have said) It can be done more benignly with a dilute solution or even coke if you have the time and are worried about corrosion. Be aware that you may remove "structural deposits" ie the pitting and corrosion may have been kept functional by the calcium protection...
I mistakenly cleaned a ships cludgie once, and had to spend a lot of time and epoxy making it functional again.

[Alan_D]

I don't know what engine you have, but Bukh strongly advise against using strong acid in their engines because of its effect on the seals of the cylinder-liners.

[DaveS]

I don't know what engine you have, but Bukh strongly advise against using strong acid in their engines because of its effect on the seals of the cylinder-liners.

It's a VP2002 circa 1989.

[sahona]

Perhaps you should focus on the block and do the push-fit pipes (if I'm thinking about the right engine) separately in case there's extra fizz where the different metals meet.

[pagoda]

Bulk vinegar -less nasty than HCl but works well if you warm it up. Anodes out !! or they will vanish rapidly. Not too much reaction with vinegar mind you.

Smells a bit chip-shoppish afterwards ....

Graeme

[DaveS]

Perhaps you should focus on the block and do the push-fit pipes (if I'm thinking about the right engine) separately in case there's extra fizz where the different metals meet.

That's fine for these pipes, but I believe that there is an internal one with small holes in it that is copper.

I'm beginning to come to the view that maybe the Fernox radiator flush idea might be better after all, since it presumably doesn't do copper pipes any harm.