Heat exchanger anode wear

Montemar

Montemar

Well-Known Member
Joined
17 Jan 2011
Messages
832
Location
Dorset
www.voltloudspeakers.co.uk
I changed the heat exchanger anodes on TAMD41B engines today, port anode completely dissolved and starboard about 20% dissolved.
I would be very interested to learn the reasons for this difference as it seems very odd to me. Little coolant came out of the starboard exchanger but plenty from the port side when I removed the threaded plugs.
Any suggestions are greatly appreciated.
 
How's your cathodic protection on drives/shafts connected to this engine? if your anodes on the shafts/props connected to this engine are gone, you'll be wearing this anode more... also another reason could be that the other engine's anode isn't well bonded. Try checking the voltages at shaft against a shorepower earth on the two engines and see the difference. if there's then there's most probably bonding issue within the boat.
 

You should check / replace these zinc every 3 months. Why should they run along the same schedule, I think it's normal.

NBs
 
Montemar said:
I changed the heat exchanger anodes on TAMD41B engines today, port anode completely dissolved and starboard about 20% dissolved.
I would be very interested to learn the reasons for this difference as it seems very odd to me. Little coolant came out of the starboard exchanger but plenty from the port side when I removed the threaded plugs.
Any suggestions are greatly appreciated.
Click to expand...

No coolant should come out, the anodes are on the seawater side.
 
Have just replaced H/E anodes on 2 x 41B. The starboard one had vanished altogether and taken much of the brass plug with it.
The port anode was about half wasted.
ASAP do replacement anodes at around £7.00.The plug around £10.00.
 
inception said:
How's your cathodic protection on drives/shafts connected to this engine? if your anodes on the shafts/props connected to this engine are gone, you'll be wearing this anode more... also another reason could be that the other engine's anode isn't well bonded. Try checking the voltages at shaft against a shorepower earth on the two engines and see the difference. if there's then there's most probably bonding issue within the boat.
Click to expand...

That is not so. The anodes from the stern gear are nothing to do with the anodes that are protecting the heat exchangers. The only reason the external anodes may be connected to the engine is to provide a path the the prop which is what they are protecting.
 
Always worth doing a continuity check between anode and nut before you insert them and then after nut to H/E. The reason for differing levels of seawater emitting is strange but not uncommon to me-I have only one engine and sometimes the seawater coming out when I change does vary significantly.If I remove the anode nut for the intercooler this is lower down than the anode nut for the h/e so an airlock can happen unless I take the h/e nut off as well.
 
check them regular, change if worn to more than 50%, save lots of pennies in the long run. Nothing to do with external anodes, they look after the stern gear.
 
Montemar said:
I changed the heat exchanger anodes on TAMD41B engines today, port anode completely dissolved and starboard about 20% dissolved.
I would be very interested to learn the reasons for this difference as it seems very odd to me. Little coolant came out of the starboard exchanger but plenty from the port side when I removed the threaded plugs.
Any suggestions are greatly appreciated.
Click to expand...
It is likely your heat exchangers sit at or just above the external water level. If the seal formed by the impeller inside the seawater pump is less in the stbd engine the water can drain back out once the engine is shutdown. Once the anode is no longer immersed it stops functioning. Because the metalwork it is protecting is also no longer immersed this is not a problem for anodes inserted from beneath but could be an issue for anodes inserted from above.

This is happens on my engines but a disadvantage is that the saltwater vestiges left behind tends to evaporate also increasing scale deposits.
 
The ASAP H/E anodes included postage which cost more than the anodes........
The previous owner of my boat swore blind on his Grannys life he had recently changed the pencil anodes, he also fibbed about one or two other jobs. :)
Suspect ..... he had no idea what I was going on about when I asked if he had the pencil anodes changed.
Doubt he knew that the boat had impellors or that they need changing more than once in a boats lifetime :)
 
You must log in or register to reply here.

Share this page

Top