Checking the levels and being aware of the ‘MAX’

Pouring blue fluid into car engine

Ensuring that fluid levels are correct for the year-round reliability of your vehicle, motoring journalist Iain Robertson states that the only way to prevent a ruined summer holiday is to ensure that your car is in good health before going.

Although the various fluid levels that we should all monitor on our cars ought not be permitted to fall below any ‘minimum’ marks, it is important to be aware that adding too much oil, water, or other fluids (in the correct places, of course!) can also cause problems.

  1. Engine Oil
  2. Prolonged, high-speed motorway trips place a high strain on engine lubricating oil, which can run at temperatures significantly higher than the cooling system, often well over 100 degrees Celsius on a hot day. Few modern cars possess an oil temperature gauge, the duty being served by a warning light instead, and low oil levels can increase the temperature of the lubricant, which will reduce its effectiveness even more.

    Every engine consumes oil. Some more than others. Yet, a falling oil level does not signify a worn-out engine. While allowing the level to fall below the minimum mark increases the risk of engine damage, filling it to the maximum and beyond can cause additional problems. Many diesel engines are designed to contaminate their oil with fuel during certain running conditions and this causes the sump level to rise naturally. If you fill the engine oil to the maximum mark (or over), you reduce the engine’s capacity to tolerate the increased oil level. Over-filling can not only cause the oil to pressurise and be forced out of the power unit but, with certain diesel engines, the oil can enter the engine’s intake valves, causing it to run uncontrollably at maximum speed, until it either explodes, or seizes.

    You should always check the vehicle’s handbook and follow its oil level checking advice carefully, as instructions vary between manufacturers.

  3. Coolant
  4. All sudden drops in the engine’s anti-freeze, or coolant, level must be investigated. However, the coolant level must be checked with the engine cold and the car standing on a level surface. When it is hot, water expands and it will not allow a reliable reading. Naturally, unscrewing the cap, when the engine is hot, raises a risk of skin burns that are caused by steam escaping.

    If you over-fill the coolant bottle, while not as serious as overfilling the engine oil, once the engine is running at full working temperature, excess water, at close to boiling-point, can be forced-out of the cooling system. This can also occur for some time after it stops. The excess spray over the engine bay not only causes ugly stains that coat everything but might also lead to a breakdown, should the vehicle’s electrics become soaked.

  5. Brake (and clutch) fluid
  6. Brake fluid levels fall gradually as the brake pads, or linings, wear out. However, you should take note of any sudden drops in level. Overfilling the brake fluid container can cause fluid to leak out, which is not good for your car, because it is a most effective paint stripper. Brake fluid’s moisture-absorbing characteristic (known as ‘hygroscopic’) also promotes corrosion (rust) and, for good measure, it should be renewed at least every other year of your life with that vehicle.

  7. Windscreen washer fluid
  8. Finally, remember that UK motoring law dictates that an empty washer bottle equates to a monetary fine and possible licence endorsement. While you might only insert antifreeze washer fluid during winter months, bear in mind that summer fluids are available that are very effective at removing dead flies from the screen. While over-filling will make little difference, under-filling the washer bottle might mean that it runs dry before the end of your trip.

    If you want clarification on any, or all, of the above tips, then pop into your local Mr Clutch Autocentre, where a professional member of the team will not only explain the details but also provide your car with an important service. After all, you do not want to ruin your driving holiday for something as simple as topping up a bottle.