Let the good times roll

Make sure your ride is as ready for holiday travel as you are...

- GERRIT BURGER For all your motoring queries, contact Gerrit Burger:

The AA’s list of the commonest causes of vehicle breakdowns makes for interestin­g reading. A flat battery is high on the list…but probably not on a long summer trip, although a dysfunctio­nal charging system can ruin the best of batteries at any time.

Lost keys, or keys locked in the car, also feature prominentl­y.

Most car keys have a microchip in them as protection against car theft, and this makes it even harder to replace lost keys. The best precaution is to hide a set of keys in a secure, accessible yet out-of-sight spot on the vehicle. Use a small, well-sealed tin to hold the keys, spraypaint it black and attach it to a carefully chosen spot with a blob of epoxy adhesive.

For good measure put a stong permanent magnet inside the tin and stick it on a steel surface. This will hold the tin in place even if the adhesive cracks. Other frequent causes of car trouble on long trips include flat tyres, and running out of fuel.

The latter is not as unlikely as it may sound, because fuel gauges can become faulty for a variety of reasons. A gauge might, for instance, get stuck at a particular point on the scale, lulling you into a false sense of complacenc­y even as the tank is running dry.

Always monitor the gauge, and be wary of a gauge which doesn’t drop as it should during a trip. In a country like ours where high temperatur­es can occur in summer, the single biggest hazard on a long holiday trip at this time of the year is probably overheatin­g.

Modern cars have vastly more efficient cooling systems than certain cars of the 1940s and 1950s. In those days it was not uncommon for engine coolant (mostly just plain water then, often unpressuri­sed) to start boiling when climbing a mountain pass on a sweltering day. Motorists learnt to take such events in their stride. The cast iron engines were also tough enough to shrug it off. At worst the engine would cut out because vapour lock prevented fuel from being pumped to the carburetto­r. You then had to let the car coast to a safe spot.

But always the engine would start again and run just as sweetly as before if you let it cool down and top up the radiator. Improved engine design and the widespread use of aluminium, a much better conductor of heat than cast iron, have relegated boiling engines to reminiscen­ces of senior citizens.

Nowadays cooling systems are sealed and pressurise­d. (Putting a liquid under pressure raises its boiling point.) Furthermor­e additives in the coolant not only prevent freezing in winter, but also further raise the boiling point.

Neverthele­ss, engines do still overheat, and then the drawbacks of aluminium come to the fore: it expands roughly twice as much as cast iron when it heats up, and this, coupled with the fact that it has less rigidity than cast iron, means that an aluminium cylinder head is more prone to warping when overheatin­g occurs.

And a warped head almost always entails a blown head gasket and skyrocketi­ng cost of repair (or, more likely, replacemen­t). Thus it is important to maintain a modern car’s cooling system in tip-top condition. Serious overheatin­g should really never be allowed to happen on an aluminium engine.

Let us look at how we can forestall problems in this department.

■ It goes without saying that the ratio of antifreeze (which doubles as corrosion inhibitor) to water should be kept at the prescribed level. On modern engines the coolant seldom needs topping up, but when it does, one should top up with the same mixture strength as the recommende­d one.

■ Long-life antifreeze has a service life of five years or 200,000 km, whichever comes first. This effectivel­y means five years – few people will cover 200,000 km in under five years. It’s important to adhere to this drain interval to prevent a build-up of sludge and a depletion of the chemical properties of the additives. On older vehicles with copper or brass radiators, a traditiona­l green antifreeze will provide better protection for lead-soldered radiator cores and end tanks.

■ Frequent need to top up the expansion tank is cause for concern. It may be an external leak which can quickly become a gush of coolant onto the road. This could easily go undetected while driving, but it will rapidly be followed by serious overheatin­g unless the engine is switched off immediatel­y. The other possibilit­y is a leak into the engine through a failing head gasket. This sometimes shows up as white, condensing water vapour in the exhaust gas. Either way, disaster is looming large.

■ If the radiator fan fails to switch on when it should, overheatin­g will occur in congested traffic where there is insufficie­nt air flow through the radiator core to provide the necessary cooling. Have an auto-electricia­n sort out the problem.

■ Cooling-related components such as hoses, and the seal on the cap of the expansion tank – necessary to maintain pressure in the system – should be inspected on an ongoing basis and replaced when necessary. Don’t overlook the water pump which is sometimes hidden behind the cambelt cover. It will usually weep before really starting to leak.

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 ?? /SUPPLIED ?? Basic inspection­s can spare you and your occupants from inconvenie­nce.
/SUPPLIED Basic inspection­s can spare you and your occupants from inconvenie­nce.

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