Yanmar 3YM series - advice on Raw Water side flush

farmer.leo

Member
Joined
8 Oct 2011
Messages
79
Looking to do preventive maintenance on Yanmar 3YM series diesel. The raw water side gets calcium buildup and would like to hear opinions on flushing material. The process is to hook up a 12V pump to the raw water just before the elbow, going backwards and exiting just before the Raw water pump into the bucket with the pump.

There is Rydlyme, which is HCL plus some secret ingredients. Have also heard of "Barnacle Buster". Then again there is Phosphoric Acid easily gotten from a restaurant supply, and Sulphamic Acid is grout cleaner.

I've read dire warnings about not using one of the commercial mixtures, but don't understand how a commercial product with HCL is safe no matter what "buffering agent" is added to the mix.

What do you use for the raw water side?
 

RichardS

N/A
Joined
5 Nov 2009
Messages
29,240
Location
Home UK Midlands / Boat Croatia
Basically you're just flushing the heat exchanger. If the seawater flow is poor you might have an impeller vane or similar blocking the flow and you're not going to solve this without removing the end of the H/E and then you might as well then remove the core. You can then clean this with your chemical (or coathanger :))and know it is 100% clean.

Richard
 

vyv_cox

Well-known member
Joined
16 May 2001
Messages
25,305
Location
France, sailing Aegean Sea.
My 3GM, which I guess has a coolant layout not a million miles from the one on a 3YM, is almost entirely composed of rubber, except for the heat exchanger and the manifold. It is around 12 years old and has done 2274.9 hours. I replaced the manifold this year, small leak at a weld, but nothing else has had any treatment whatsoever. I see no reason to act otherwise.
 
Top