Diesel Engines - Cause of Early Failure How to Entend Its Life
From: The Liveaboard Listserv (with modifications)
Primary causes of diesel engine failures:
Too much unburned diesel fuel in engine. Diesels run cold when not under load and at low idle. This means they "wet stack"; not all the fuel burns. Some fuel ends up on top of the pistons. This unburned fuel sticks to the carbon on top of the piston. It turns effectively into coal. Some of it also runs down the cylinder walls which destroys the lubricating film of oil, greatly increasing cylinder and ring wear, and further can contaminate the oil which can distroy the main bearings as well as other moving parts in the engine.
Racing an engine immediately after start is VERY bad. However, after 15 to 30 seconds there is no harm in setting a fast idle for warm-up. The key before increasing the RPMs is to make sure oil is under pressure in all places in the engine, which usually happens in the first 15 to 30 seconds.
Diesel engines overheat due to poor maintenance or running too hard for too long.
Poor maintenance of oil and cooling systems.
Methods to prolong the life of a diesel engine:
Avoid prolonged idling at no load. When you must idle, keep the RPMs at approximately 1,000 after the engine has been running for a minute or so. (Don't forget to drop it back before engaging the transmission!)
Avoid pushing your diesel too hard. While it is good to run your diesel under load, it is not good to run for extended periods under a full load.. Throttle back a bit and increase the life of your diesel.
Perform recommended maintenance on schedule. This includes changing oil and filters, cleaning heat exchangers, replacing impellers, and maintaining proper coolant balance in the freshwater side. It also means changing zincs and maintaining proper backpressure in the seawater side so the exchangers remain full of water (and not air) to maintain an appropriate flow rate (too fast is as bad as too slow!).
Lay up and commission you diesel properly. Leaving a diesel sit for a month at a time is not good as it can cause corrosion and condensation damage. Fog your engine according to the manufacturers directions and plug the exhaust port with an oil-soaked cloth.
When you start your diesel, get it up to normal operating temperature. If you're going to start the engine, run it long and hard enough to get to full operating temp for a while (an hour or so.)
Install block heaters unless you live in South Florida or similar locales. These will keep condensation out of your oil and that makes a huge difference as well.