There is a lot of confusion out there about servicing your motorhome vehicle. It's one of the most expensive "automobiles" you'll likely ever own, so it's vital that you keep it in tip-top condition.
The way we use this "engine" is also incredibly unique. We're unlikely to reach the servicing kilometre requirement, and we might store the engine unused for months at a time and then take it out for long stints on the road.
Trying to save a few bucks on servicing, while it might seem like a good idea at the time, eventually it could cost you thousands in motor trouble and reduced resale value. People love to purchase something with a reliable service history. TrailLite require it as a condition of selling your vehicle on behalf!
Often your vehicle manual will explain the servicing requirements of the engine part of your motorhome (the habitation will likely carry additional servicing requirements designed to keep your warranty valid). The most common thing you'll see is a yearly requirement or X number of kilometres. The thing is with motorhomes we rarely reach the number of kilometres needed for a service, but that doesn't mean you shouldn't get one each year.
Like just about everything else, motor oil has a lifespan. Even the best oils eventually require you to change them. Historically, many motorists like the convenience of replacing oil with the seasons, visiting the quick lube or pulling the ramps out of their garage each spring and autumn.
Motor oil can deteriorate by becoming contaminated, the additives depleting over time or both.
Servicing each year is also a good opportunity for everything to be checked over and "cleaned out" ready to run smoothly.
If you like detail, I've put together the facts about oils and engines. I'm a mechanic by trade and spent years running auto service centres to understand first hand what can go wrong when servicing isn't followed correctly.
How oil becomes contaminated
Base oils are the backbone of the finished lubricant that ends up in your engine. They can be conventional, synthetic or a combination thereof. They're responsible for lubricating components, which reduces friction and protects against wear.
Base oils can lose their effectiveness over time due to a few different factors.
Oxidation – The interaction between oxygen molecules and motor oil molecules naturally leads to chemical breakdown. Just as oxygen causes a cut apple to brown or exposed metal to rust, it breaks down base oils and reduces motor oil's effectiveness. Oxidation can lead to increased oil viscosity, which negatively affects energy efficiency. It also causes the formation of harmful deposits and sludge.
High heat – 'Today's engines run hotter than ever before, with temperatures up to 112 degrees, and even higher if towing or hauling — the rate of oxidation for oil doubles for every 7-degree increase in temperature.
Moisture – Your vehicle is also subjected to temperature swings, even when it is parked in the garage. Those temperature swings cause condensation to form inside your engine, leading to water contamination. Leaving a vehicle parked for extended periods or taking short trips that don't allow the engine to fully warm up allows water to remain in the oil rather than evaporating and exiting through the tailpipe. Water can lead to formation of sludge.
Viscosity loss – A lubricant's viscosity is its most valuable property. Viscosity has a direct bearing on wear protection, and your engine is designed to operate best using a motor oil of a specific viscosity (e.g. 5W-30). The intense pressure the oil bears as it's squeezed between moving parts, like the piston ring/cylinder wall interface, can tear apart, or shear its molecular structure, leading to viscosity loss. Suddenly, the 5W-30 motor oil your engine was designed to use is now essentially a 5W-20 oil, and wear protection may be compromised.
Fuel dilution – Fuel can wash past the piston rings and contaminate the motor oil, causing it to lose viscosity. Frequent short trips that don't allow the oil to reach normal operating temperature can be especially problematic because the fuel won't volatilize and exit through the PCV system. Excessive fuel dilution leads to sludge and varnish, requiring the oil to be changed more often.
Additive is designed to deplete
Additives are added to base oils to reduce destructive processes and enhance beneficial properties. For example, antioxidant additives help slow the rate of oxidation. Detergency additives help prevent deposits and sludge while cleaning pre-existing deposits. Anti-wear additives are added to some lubricants to form a sacrificial barrier on metal components and help prevent wear.
Since they're sacrificial in nature, additive depletion is one of the primary reasons motor oil loses its effectiveness and must be changed.
Though all motor oils eventually deteriorate, synthetic oils last longer than conventional oils and deliver improved protection against wear and deposits. They're formulated with base oils that are more resilient to oxidation and heat, while their additives also typically offer enhanced performance.
Basically what all of this means is that regardless of kilometres your vehicle servicing should be kept up to date. The very way we use motorhomes, store them, take short trips here and there, tow or carry heavy loads means we need to keep looking after the engine that drives them.
Change the oil every year, get a service annually and keep up with yearly maintenance. We'll blog more about that later... for now don't forget to change your oil!