The lifeblood of your vehicle

In Technical by Glyn DemmerLeave a Comment

Driving off-road and towing can put a vehicle under a good deal of stress, especially to the engine and gearbox lubricants as well as your differentials. It is advisable to use good quality lubricants and change them regularly in line with your vehicles servicing schedule. If you have driven long stretches in deep water, it is also worthwhile to check your differential oil – oil that has mixed with water takes on a milky look.

There are many lubricants available for your 4×4 as well as general passenger vehicles. It is important to use the lubricants specified by the manufacturer in all cases.

Oil viscosity refers to how easily oil pours at a specific temperature. Thin oils have lower viscosity and pour more easily at low temperatures than thicker oils that have a higher viscosity. Thinner oils reduce friction in engines and help engines start quickly during cold weather. Thick oils are better at maintaining film strength and oil pressure at high temperatures and loads.

Viscosity is rated using grades specified by the Society of Automotive Engineers (SAE) and range from an SAE 10 for a thinner oil to an SAE 140 for thicker oil. Multigrade oils are specified and formulated and can cover a wider range of climatic conditions. Oil performance is rated according to specifications established by the American Petroleum Institute (API) and fit into 3 different brackets:

  • S for petrol engines
  • C for Diesel engines
  • GL for transmission components

Each letter is followed by a number for transmission oils and a letter for engine oils, an SH oil being of a better grade than an SG which in turn is better than an SF oil.

So, we get a variety of oils for various applications:

  • Engine oils are designed to reduce friction, aid engine cooling and remove abrasive particles from moving parts. These particles get taken up in a full-flow oil filter and in many cars a bypass filter. The oil filter should be changed every time engine oil is changed.
  • Transmission oils fit into two categories, namely manual transmission oil and automatic transmission fluid. Manual transmission oil is thicker than engine oil. It aids cooling, reduces wear and assists gear selection. This oil would typically also be used in the transfer case. Automatic transmission fluid (ATF) is a thin lubricant that lubricates all moving components, assists with the actuation of various hydraulic circuits and is a drive medium within the torque converter.
  • One would also get front and rear axle oils which, depending on the type of axle/differential, could be a multigrade extreme pressure oil or a hypoid oil.

Various other components require greasing, although in the case of wheel bearings more modern vehicles are fitted with sealed units which simply get replaced when wear is detected.

To ensure a long and reliable service life of your vehicle, regular lubrication is essential as are the routine maintenance checks and replacement of wear and tear components. Lubricant specifications and quantities are found in your owner’s manual and are also known to your servicing dealer. The lubricant levels should always be checked on a level surface using the filler level plugs or, in the case of the engine, the dipstick.

The last type of lubrication is for squeaks and parts that may stick and not function easily. Keep the following on hand for these little jobs:

  • Dry lubricant for lock strikers.
  • Graphite for lock cylinders.
  • Engine oil for hinges and linkages.
  • Silicone spray for plastic and non-metal parts.
  • WD40 or Q20 for a plethora of uses.

As the title says this is the lifeblood of your vehicle if you neglect it your vehicle will eventually let you down and that is not something you want far from home out in the bush. So, look after the system the same way you look after yourself, and you will be assured of many happy kilos on the clock.

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