It has been a surprise to me how much seaweed and other dirt accumulates in the heat exchanger for the gear box even though there is a strainer at the intake point.  Amel recommends that the heat exchanger be cleaned out yearly and it‘s definitely necessary.   I checked the manual for my Volvo D3-110 engine and it says the following on page 104:

„Volvo Penta recommends that a seawater filter be fit- ted to guarantee the correct cooling water flow to the engine and reverse gear. Otherwise there is a risk of contaminants in the seawater blocking the reverse gear cooler and other cooling system components.“ I read this to suggest that there should be a second filter in the engine intake line after the main intake strainer and before the heat exchanger.  I wonder why Amel isn‘t doing that and if anyone has done so.  Cleaning out the heat exchanger is a difficult task, cleaning out a second filter would be a simple thing to do on a regular basis.       

Joerg Esdorn
Amel 55 #53 Kincsem
Vigo, Spain