We think that the cancer of D4 and D6 VP engines are the Charge Air Cooler (CAC) and Heat Exchanger (HE). On my boat, I strip CACs every 2 years and HEs at least every 4 years. However, this solution is certainly not useful for someone who does not do it by himself, as this is difficult to accept, both in terms of time and money.
In both parts, I think there is a fault in the non-metal end covers. Firstly, because one pipe from the cooler is routed at an angle of 90° and the radial acceleration or the angular velocity of the water causes that O-ring starts eventually to leak. However, this is a minor part of the problem. A major part of the problem is the material of the original cover which doesn’t fits 100% (especially when the cover is used more times) and even slightly deforms at higher temperatures in the engine compartment. Because we believe that this will greatly extend the lifespan of the coolers, we developed an anodized seawater resistant aluminum cover for the D4 and D6 CAC (22092538). Tests showed a better sealing of the cover (tested with water and air at higher pressures than occur in the engine), less temperature deformation and improved cooling of the cooler.
