The main function of the shock absorber is to ensure correct and continued contact of the tire with the ground.

The shock absorbers, together with the tires and the brakes, are the safety elements on a vehicle that are subject to the greatest wear.

The shock absorber complements the suspension, avoiding up-and-down and sideways oscillations in the vehicle. They work simply. There is a piston that slides inside a cylinder filled with oil or gas. Some holes allow the contents to pass between the two cavities created by the piston when it slides

With use and losses of gas or oil, the shock...


The spark plug is the element whose job is to produce petrol combustion inside the cylinder. To do this it must produce a spark that jumps between its electrodes. With a motor turning at 4,000 rpm, the number of sparks jumping in each spark plug is 2,000 per minute (33 per second), which combined with the high temperatures, high pressures, vibrations, etc., gives some idea of the extreme running conditions it is subjected to.

One of the fundamental characteristics a spark plug must fulfil is heat evacuation. Because of its position (in the combustion chamber) the spark plug is exposed to...


Timing belts

The timing belt has the job of transmitting movement from the crankshaft to the camshaft. Furthermore, they usually activate other engine elements such as the water pump or injection pump (in diesel engines)

Over time and as a result of the tough working conditions they are subjected to, the belt wears and needs to be replaced. The manufacturer sets the replacement interval in both kilometres and time. It is imperative to respect these replacement intervals to avoid possible belt breakage and, as a result, costly damage to engine workings.

If a replacement interval is not set,...


Oil filter

This is a vital organ in engine operation as its job is to keep the lubricant perfectly purified, retaining abrasive elements like air-borne dust or metallic particles resulting from wear of moving parts.

It also eliminates products resulting from combustion that manage to get into the housing, and substances that are produced during degeneration of the oil itself. Given that the cost is minimum and the damage that can be produced in the engine is great, it is advisable to change the filter when changing the oil, and always when the manufacturer determines so in the vehicle...


The battery is an energy store whose function is to start the vehicle engine. Energy is stored by a chemical process between two lead plates and a liquid called an electrolyte made of water and sulphuric acid.

In batteries requiring maintenance it is important to check electrolyte level in each of the six vessels that must be one centimetre above the highest part of the plates. Otherwise, distilled water must be added to reach the correct level. It is very important not to use tap water as it contains minerals that interfere in the chemical reactions and damage the plates.

It is not...


Brake fluid

Brake fluid is a hydraulic fluid based on alcohols and glycerines.

This liquid has a high boiling point, which makes it the ideal liquid for this circuit given the high temperatures reached there, particularly in areas near the brake cylinders.

When handling this liquid, care must be taken not to touch it and spills must be avoided as it produces a stripping effect on bodywork paint.

The Brake fluid tank level should be between the minimum and maximum.

Brake fluid is hygroscopic, i.e., it can absorb humidity contained in the air. This means that over time the liquid contains enough...


The main functions fulfilled by oil are- reduce wear to lower consumption and improve engine performance, protect mechanical elements from wear and corrosion, keep motor parts clean by carrying away impurities that are eliminated in an oil change, and contribute to removal of heat generated by the engine.

It is not just mileage that deteriorates the engine oil. Internal friction between motor parts generates detachment of abrasive metallic scraps. These end up mixing with the oil to give it the blackish tone seen on the oil level dipstick. The oil filter partially eliminates these...


The tires are the only point of contact with the road. They affect power steering, brakes and vehicle grip.

The minimum depth of tread on wheels must be at least two millimetres. Furthermore, there should be no irregular wear, which would indicate a suspension fault.

The condition of the rims is also important.

Check that they show few signs or scratches and move them from left to right and vice versa. If a creaking or other strange sound can be heard during the check, there could be serious problems in the axles.

It is very important to make periodical checks in cold of the tire’s inflation...


The exhaust system has to fulfil various functions:

Safely route the engine exhaust gases to the rear of the vehicle

Reduce engine noise levels

Maintain engine performance

Reduce or eliminate certain engine emissions

It is extremely difficult to determine exhaust system life. There are many factors involved, including regional climate, driving style and whether the system is single or double. However, as a practical general rule, the typical life span of an exhaust system from the high quality accessories market should be near to two or three years, depending on driving style and the factors...