descaling volvo cooling system - rydlyme

PaulR

PaulR

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planning to descale our volvo 2030b engine and have read about others using rydlyme - pls see below extract from instructions:-

Use RYDLYME at an ambient temperature.
Vent circulating solution to atmosphere. Some adverse reactions may occur with some alloys of
aluminium, magnesium, zinc and/or other sacrificial/inferior metallurgies.


Does the volvo raw water/freshwater cooling system contain any vulnerable aluminium ? Presume not as others report success with rydlyme or perhaps it is not left in the system long enough to cause any problems , be grateful if anyone who knows can clarify if there is vulnerable aliminium in the system or length of time and concentration of rydlyme used before I go ahead - thanks
 
I've just done one of my TAMD61A engines as I noticed the engine temp was increasing to 200F at cruising speed. Normal cruising temp should be about 180F.
The rydlyme needs to be mixed 50/50 before use and in my case we needed three people, one on the engine start/stop, one on the pontoon watching for the first sign of rydlyme coming out of the exhaust and one in the engine bay pouring a continuous mixture into the engine. We premixed a total of 15 litres, closed the seacocks and took off the raw water filter cover. Engine was started on tickover and the solution was poured in until the engine was stopped at the first sign of the brown Rydlyme coming out of the exhaust. Now we know the raw water capacity of the engine we can now repeat the operation with two people. We then left the rydlyme in the engine for approx. 22 hours and then opened the seacock and flushed the engine through. In our case we have zinc engine anodes which we replaced as per the advice contained in the instructions. Once flushed we went for a sea trial and after 20 mins cruising the engine temp had returned to 180F so we then went to WOT for a further 20 mins and the engine temp didn't go above the 180F. We have just returned from a direct trip to Guernsey and the engine temps have remained constant throughout. From my experience I can happily recommend rydlyme.
 
What was the capacity doing it like the david? I was going to rig a pump system but your way sounds much easier!
 
Only slightly o/t, but recently I spoke with the MAN chief engineer of the IT importer, and he strongly advised against cleaning of the raw circuit "in place", because there are also some o/r and other rubber bits which would get corroded and must be replaced upon cleaning anyway, so their recommended procedure (btw, suggested every two years, though I don't think anyone with MAN engines has ever followed that timeline religiously) is to remove the heat exchanger and the aftercooler - which needless to say, increases the costs a fair bit :ambivalence:

Makes me wonder if it isn't worth trying what David435 is reporting also on MAN engines...
Wadduthink, folks? Has anyone ever done that?

PS:
on second thought, I don't think that VP engines can have zero non-metallic parts anywhere in the raw circuit (o/r, seals, hoses, whatever) - including the wet part of the exhaust, which depends more on the boat builder than on the engines, but I've yet to see any exhaust system without any rubber parts, at least in the final wet section attached to the hull.
So, is this Rydlyme stuff certified as non-aggressive against all these parts?
 
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I've used the stuff a couple of times, and haven't noted any problems with rubbers, at least on my Volvos. I always remove the anodes however, as it will eat zinc. I circulate mine with a 12V pump I bought on Ebay for £10. I disconnect just after the pump and before the exhaust to make a closed circuit and leave circulating for a few hours (I leave for 2-3 hours) with a 50/50 mix.
I think the issue with it, is that if you have a lot of build up, with blocked tubes, it's unlikely to totally unblock them as there is no flow in the first place, so I've still had to disassemble parts of the cooling system to rod totally blocked tubes.
 
What was the capacity doing it like the david? I was going to rig a pump system but your way sounds much easier!
Click to expand...

Hi Farsco
On the TAMD61A engines the capacity of each engine was approx 14 litres, a mixture of 7 litres rydlyme and 7 litres water. The method was proposed to me by a volvo mechanic who is well aware of all the rubber seals involved on a Volvo engine and advised a 24 hour soak produced the best results.
 
David435 said:
Hi Farsco
On the TAMD61A engines the capacity of each engine was approx 14 litres, a mixture of 7 litres rydlyme and 7 litres water. The method was proposed to me by a volvo mechanic who is well aware of all the rubber seals involved on a Volvo engine and advised a 24 hour soak produced the best results.
Click to expand...

Thanks very much.

I was going to do a closed circuit pump loop but as with all these things, you can create more issues than you solve by trying to take things apart. I have no cooling issues at all so it's more a good housekeeping exercise. Your method would be much simpler and I don't need to disturb anything unnecessarily.
 
Dear David , Your method !!!
Need your help!! I am trying to clean heat exchangers on D6 370 engines with 5% phosphoric
acid solution .When I pour solution to the filter/strainer ( seacock closed, engine running ) the
solution remains in the strainer instead being pushed out of the boat . Would you know why ??
many thanks
Michael
 
Why use phosphoric acid?

Hydrochloric (brick cleaner) is more usual in Mallorca. I know on here many use Rydlyme, but that as its base is HCL in any event and both eat zinc so I am not really sure as to the difference other than £. HCL is sold in clannish supermarkets for E1 for 1.5 litres. Cheaper than most water!

Re your issue is the impeller ok? The engine should suck anything in the strainer, but if you let air get in I imagine that it is possible it could stop sucking. Keep the flow up, Try with water first ... acid is nasty stuff.

Your anodes will be destroyed so either remove or replace.
 
poninski said:
Dear David , Your method !!!
Need your help!! I am trying to clean heat exchangers on D6 370 engines with 5% phosphoric
acid solution .When I pour solution to the filter/strainer ( seacock closed, engine running ) the
solution remains in the strainer instead being pushed out of the boat . Would you know why ??
many thanks
Michael
Click to expand...

With the sea cocks closed it has nowhere to go, unless you have rigged a circular cooling circuit.
 
CLB said:
With the sea cocks closed it has nowhere to go, unless you have rigged a circular cooling circuit.
Click to expand...

Yep, if this is an early d series engine the raw water strainer is after the pump,so if you've closed the intake valve the pump has nothing to push up into the strainer to push the acid out.

Newer d series have the strainer before the pump I think.
 
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