Descaling raw water cooled engine

[Rafiki]

Prior to lift out I am considering attempting to descale the innards of my 26 year old Bukh 20 raw water cooled engine by running descaling fluid of some sort through it in a continuos loop. I know that bukh doesn't recommend this but I also know others have tried it with some success - or at least no dire consequences.

I have the continuous loop arrangement made up. My question is what descaling fluid to buy and how much water does the engine take?

Has anyone done this and what fluid did they use?

Regards

Andrew

 

[VicS]

Fernox DS-3. A sulphamic acid based central heating boiler descaler has been used by some. Readily available from plumbers merchants and DIY stores

Another possible choice is Rydlyme

 

[capt_courageous]

Hi Andrew I suspect that the ' central heating ' stuff is to get rid of limescale while is salt that is most likely to block up raw water cooled marine engines. I took the head off my old Volvo and found that four of the eight small waterways between the head and the block were more or less completely blocked by salt. In fact only two were completely clear. The salt was as hard as the stuff they put on roads. I cleared them with a screwdriver rather than chance a broken drill. Sadly it was all to late, the engine must have been overheating for years. Got a nice new Beta, cost an arm and a leg but is smooth and quiet.

 

[emsworthy]

Hi Andrew,

I seriously considered doing just this when it was apparent the flow of raw water through our Lombardini engine was low, plus I couldn't get the new pencil anode in so I knew something wasn't right. In the end I bit the bullet and removed the heat exchanger tube nest and was gobsmacked by what I found!

Hard scale and salt deposits that needed a lot of careful chipping to remove, it was amazing any water passed through at all! If you are using a chemical that could even begin to touch what I had I'd be very careful you don't spill any!!

My recommendation is you take a couple of extra hours to remove the heat exchanger at least you then know it's been done properly and it really isn't that hard once you get going.

Good luck.

Tim

 

[longjohnsilver]

Rydlime is what I've used and does the job. Someone I know had an overheating problem, gradually increased over a period of several years from 75 to 90C. Rydlime brought it back to 75. My experiences whilst not so extreme have been good. Does what it's claimed to do.

 

[saltwater_gypsy]

Isn't full strength Coca Cola a traditional fisherman's descaler. Remember to wear protective clothing etc when handling!!!

 

[Twister_Ken]

I've heard Calgon suggested. No experience of efficacy myself.

 

[alan_d]

My recommendation is you take a couple of extra hours to remove the heat exchanger at least you then know it's been done properly and it really isn't that hard once you get going.

If you read the original post you will see that it refers to a "raw water cooled engine", so there will be no heat-exchanger to remove.

 

[morgandlm]

I have used Fernox in my Bukh DV10 without any problems but could not testify to any measurable improvement as a result. The guys at Bukh UK generally provide very sound advice. They were very concerned about the effect of such products on the liner O-ring seals and said not to use them. They were particularly concerned about Rydlime which I believe is a fairly strong acid. Dismantling what you can and probing about inside seems to be their preferred option but perhaps you can get away with Fernox or similar.
Morgan

 

[Rafiki]

Fernox etc

Thanks all - I think I will try the fernox on the basis taht it may help and unlikley to do any serious harm.

Regards Andrew

 

[emsworthy]

If you read the original post you will see that it refers to a "raw water cooled engine", so there will be no heat-exchanger to remove.

Note to self... "Must remember to read orginal post carefully!"

 

[RobBrown]

Just saw your post. For what its worth, I took off the exhaust manifold on my Bukh 20 and treated this with Fernox soak and it most certainly removed about 90-95% of the substantial deposits within it, but having received the same warning advice from Bukh UK about using it on the main engine block, I restricted cleaning of the accessible waterways on this just by mechanical removal.

Vide recent post from me re an overheating Mariner 2T, Fernox also used on this ( running engine in a 10% warm soln) and definite improvement noted and no adverse effects , at least so far!

 

[longjohnsilver]

Isn't full strength Coca Cola a traditional fisherman's descaler. Remember to wear protective clothing etc when handling!!!

An old wives tale. Tried it earlier this year as I had a bottle of coke hanging about. Poured it into heat exchanger and left for a day or so. Did absolutely nothing!

 

[psmonarch]

Can I give you a bit of advice from the steam boat perspective? ....I know it seems odd, but dealing with scale and not damaging o rings and seals is an annual job for us!!

Give this product a try, it will last you years and does not contribute to the dangerous trade of swindlery!

http://www.ibhs.co.uk/product.asp?strParents=157&CAT_ID=250&P_ID=700

Matt