Weekly Car Checks

These are the checks most people skip. They are also the ones that catch a £300 head gasket failure while it is still a loose hose clip.

The weekly checks on the vehicle may well be the ones that are ignored, but these are the checks that display early signs of trouble. For example, the engine coolant level is found to be low; this leads to a quick look around the engine bay and a poor hose connection is found on the radiator. A few minutes later, aided by a screwdriver, the leak is fixed at zero cost, and the possibility of a £300-plus head gasket failure has been averted. The time taken is minimal and the savings made can be massive.

Aside from the time element, the weekly check procedures require little in the way of equipment. A tyre pressure gauge and a tread depth gauge are all that is required. Assuming that the owner has access to the correct materials, the regular vehicle checks and top-ups should take no more than 15 to 20 minutes to cover the following: tyres, battery, brake fluid, engine oil, engine coolant, windscreen wipers and washers, lights and fuel.

Tyres

As covered in what a car tyre actually does, a tyre in good condition is capable of removing five litres of water per second from the road contact patch — vital if grip is to be maintained on a wet road surface at 70 mph.

Looking at tread depth, the legal minimum is 1.6 mm across the centre three quarters of the road contact area and round the tyre circumference. The tyre must be free from cuts that expose the underlying structure, bulges that betray a structural fault, any bald areas worn sufficiently to expose the tyre structure, and any other defect causing the tread to separate.

Using the tread depth gauge, always measure the tread at its minimum on the tyre contact area. It is this minimum that can earn you a fine and penalty points, not the maximum. If your check reveals uneven wear, get it investigated by a garage or tyre specialist, as this can suggest a mechanical fault with the suspension which in turn can affect the handling of the vehicle. With the vehicle sat on the road there will be four patches that cannot be checked, so do not forget to move the vehicle backwards or forwards to allow checking of these areas.

A brief note on tread wear indicators: these are raised bars moulded into the tread, equally spaced at five or six points around the tyre. These bars become easier to see as the tyre wears, and when the tread is flush with the bars, minimum tread depth has been reached. A useful addition, but no substitute for an accurate depth gauge.

Moving on to tyre pressure, all pneumatic tyres have a design operating pressure range and car manufacturers publish these figures in the vehicle handbook. This figure may vary depending on the use to which the vehicle is put; high speed or laden, the pressure may be 5 psi higher than the figure for normal use. It is important that when the tyre pressures are checked the tyres are cold, and should you need to top up, always slightly over-inflate and adjust down to the correct reading. This will negate any residual pressure in the gauge unit supplying the air.

Battery

Moving into the engine bay — and of vital importance, when the engine is cold — external checks on the battery consist of making sure that it is secure and that the positive and negative connections are clean and tight. By clean and tight, I mean free from the build-up of corrosive salts, and tight enough to resist a wriggle test. Within the scope of weekly checks, there is nothing more to do.

Brake fluid

The next port of call is the brake fluid reservoir, and providing the level of fluid inside can be seen, all that is required is a visual check ensuring that it sits no higher than the maximum and no lower than the minimum. The maximum and minimum marks may take several forms including lines, arrows or words; if you are in any doubt refer to the vehicle handbook or ask at a reputable garage.

Most fluid reservoirs are fitted with a level warning sensor which, when activated, operates a dashboard warning light. This is no substitute for routine physical checks — it is there merely to warn the driver of a sudden loss of fluid during a journey. On the subject of level: as the brake friction material wears away during its service life, the level in the reservoir will very gradually drop. Providing the level does not drop suddenly, indicating a leak, topping up to the maximum is fine.

Engine oil

Ensuring that the vehicle is on level ground, withdraw the dipstick, wipe it and replace it, then take it out again and check the indicated level is between the maximum and minimum — no higher and no lower. It is important to note that when checking the level, the dipstick must not be held with the marked end uppermost, as this will allow the oil sample to move along the stick and give the impression that the level is higher than it actually is.

It may well be that the engine in question runs well and is very reliable but has a tendency to use oil. Providing that this usage does not exceed one litre per 800 miles, engine wear can be considered to be within acceptable limits.

Should topping up be required, add a little and re-check — it is far easier to add oil than be forced into draining some out from underneath. The amount of oil required to take the level from minimum to maximum can be surprisingly small, and in some cases a third of a litre is sufficient. When oil has been added, always allow two to three minutes for it to reach the sump at the bottom of the engine, and a little longer if the engine has been left standing overnight.