SERVICE :: Service Tip #11

Why do maintenance?

On a recent trip down island, I was told by several customers that they haven’t changed oil in 2-3 years, because the engine does not run very much. They quote a 500 hour oil change interval from the Operator’s Manual and point that they only put around 100 hours per year on the engine. So why should they change the oil or perform any maintenance? The simple answer is because it will save them money.

First of all, oil oxidizes. Our Service Manager, Dan Durbin, says: “Oil molecules combine with oxygen molecules over time forming acids, varnish and sludge. This can cause bearings and internal metallic parts to erode. The base oils alone cannot meet the current needs of today’s lighter, high output engines. A highly complex additive package is added to the oil to make it last longer and perform better. But the ability of the base oil and additive package deteriorates over time, becoming enemies of engine life. I had a jar of oil that came out of an engine oil pan that looked like thick molasses due to "extended" oil change intervals performed by the owner. I kept the jar to show people. As it sat on my desk it got thicker and thicker, until finally it was a thick goo that did not flow when I turned over the bottle.

Condensation also builds up in an engine that doesn’t run, which results in water contamination in the oil.

Low running hours are a terrible thing for a diesel engine. A diesel is happiest when it is running with 70% or more load on it. Running the engine 24 hours/day, 7 days/week will result in the longest running hours from an engine. Sitting around idle is one of the worst things that can happen to an engine.

That is why engine manufacturers always give a time period in the maintenance schedule, as well as running hours. Typically oil changes are given as a certain number of hours or 12 months, whichever occurs first.

Another important maintenance item to not skip is flushing the cooling system. Check our website, for Service Tips on coolant quality. This is one of the most insidious problems diesel engine owners face. Poor coolant quality results in many diesel engine problems or failures in the Caribbean every year. The only proper coolant is distilled water, or glycol mixed with distilled water. Even then, the coolant should be flushed annually.

Why do we need glycol (anti freeze) in the Caribbean? It never freezes. The reason is to keep your coolant from reaching its boiling point and evaporating. Water boils at 212F (100C). New generation engines routinely run as high as 226F (107.7C). They don’t alarm until 235F (112.7C) or 244F (117.7C). Plain water would evaporate at those temperatures. A 50/50 mixture of glycol and (distilled) water raises the boiling temp of your coolant to 225F (107C). The same mixture with a 7 PSI (0.5kg.cm2) pressure cap is raised to 239F (115C). So a glycol mixture and proper coolant system pressure is critical. Remember never to exceed 50% glycol in your cooling system.

Other maintenance items that are recommended may not be as important to the overall life of the engine, but will result in better fuel consumption, lower soot and noxious exhaust fumes, and quieter running. These include checking, calibrating and repairing (as necessary) the injectors. Also included is adjusting the valves. The injection pump itself has recommended service interval as well. If your engine has a timing belt, changing that is critical. Consult your operator’s manual for the items required by your engine manufacturer.

Doing these maintenance items can greatly extend the life of your diesel engine. This not only saves you money, but also makes sure that diesel engine will be there when you need it. The easiest way to extend the engine’s life is by running it. If your diesel engine is in a boat, make sure that it is run once a week, ideally under load. If the engine is in a standby generator, make sure the exercise timer is activated and set to run, under load, once/week. Ideally run them for an hour. This will heat up the oil, dry out the moisture and recoat all the metal surfaces with fresh oil.

Changing oil and coolant is very cheap compared to changing an engine.

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Tel: +1(284)494-2830/440-2830

Tel: +1(284)494-2830/440-2830

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