Our mechanical engineer continues with a series of thematic Q&A articles to assist the average motorist in Singapore.

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Our mechanical engineer continues with a series of thematic Q&A articles to assist the average motorist in Singapore.

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The second question-and-answer article in our newly introduced Torque Shop series for 2017 is, like the first one, about troubleshooting old cars, which tend to develop problems as they accumulate ever higher mileage and experience increased wear-and-tear. The questions here are about the instrument panel’s warning lights which drivers dread.

When I start my car these days, the engine check light stays on for longer than before. Should I be worried?

The engine check light comes on whenever the engine control unit detects a fault or an error.

It could be something as simple as a leak in the intake air hose, or something a little more complex, such as the throttle position sensor.

If the engine check light comes on intermittently or stays lit only momentarily, the problem is unlikely to be serious. However, it does mean a fault exists.

It is advisable to determine the exact cause of the warning and rectify the problem, as the faulty component could affect engine performance, emissions and fuel efficiency.

Take the car to a workshop (official or “outside”) that has the equipment to conduct an electronic on-board diagnosis.

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My car’s brake fluid level indicator lit up the other day. As I felt the brakes were still working well, I topped up the brake fluid reservoir at a nearby petrol station. The warning light went off. How exactly is brake fluid consumed in the braking process? My car is two years old.

Unlike engine oil, brake fluid does not burn up anywhere in the braking system. So the first thing to check when the brake fluid level drops is whether there are any leaks in the hydraulic brake lines.

Any brake fluid leak must be fixed immediately, or it will ultimately result in total brake failure.

Unless the vehicle is damaged (perhaps in an accident), such leaks are highly unlikely, especially in a two-year-old car.

There is another reason why the brake fluid level drops. When brake pads start to wear and thin out, the pistons in the brake calliper move further outwards and the space thus vacated fills up with fluid from the reservoir.

In cars that do not have a brake pad wear indicator, the fluid level warning serves as a signal that the pads need replacing.

When new pads are fitted, the calliper pistons are pushed back, causing the fluid to return to the reservoir. The car’s brake fluid level will rise back to its normal level when all the brake pads are replaced.

The “Low Coolant” warning light in my car came on. I checked the coolant tank and noticed it was below the minimum mark. I topped up to the maximum mark and the warning light disappeared. But about a week later, it came on again. This has been going on for five weeks, but I do not see any leakage anywhere – whether in the engine compartment or on the floor where I park my car. What is the problem?

Your car definitely has a leak. The reason you cannot see the source is likely because it is a small leak, which evaporates when the fluid falls on the hot engine.

When your engine is switched off, there is no pressure in the cooling system and the coolant may not leak.

You should send your car to a workshop which can pressure- test the cooling system. Such a test will simulate the pressure in a running engine and uncover the source of the leak.

It is important to have this fixed quickly because the coolant leak can only get worse. If so, it could lead to engine overheating and costly damage.