Ask the Mechanic

MY CAR’S ENGINE OIL LEVELS DROP FAST AND CAUSE SMOKE

Hello Paul, my car is UAP series. Of late, its oil level drops so quickly and it produces smoke more than before. What could be the cause? 

Elly Biliku

Hello Elly, when car engine oil levels excessively reduce between drain intervals (service) and your exhaust pipe produces a lot of blue smoke when you accelerate, it usually means that the engine is burning oil. Ordinarily, an engine; new or old, will lose about a quarter to half a litre of oil between a 5,000km drain or service interval. This oil is channeled through the engine crank case venting system to aid smooth engine running.

An engine usually burns excessive amounts of oil when it has severe wear and tear of piston rings. The extent of piston ring wear or damage on each cylinder can be assessed by carrying out an engine compression test using a compression test kit. The compression test will show the condition of engine valves, valve seals as well as piston rings, under load. The outcome can motivate the mechanic to dismantle and inspect the engine for possible overhaul.

During inspection, the piston rings, pistons, cylinder walls, crank shaft, main and piece bearings, valves and seals will be examined to determine whether they too have suffered wear and tear. This will also determine the extent and cost of your car engine repair. Find a professional garage to inspect your car and give you a repair budget.

WHAT IS CAUSING THE CHECK ENGINE LIGHT AND REDUCED ENGINE PERFORMANCE?

Hello Paul, I drive a Toyota Harrier 2007 model whose performance and fuel efficiency has reduced. When I drive above 80km/hr, the engine check sign appears and stays on until I switch off the engine. What remedy do you propose?

Godfrey

Hello Godfrey, the check engine light means there is an emission system fault with your Toyota Harrier engine. A faulty emission system will reduce fuel economy and engine performance. Emission system faults can be caused by any of the engine components which affect the emission system.

These range from ignition system (ignition coils and spark plugs), fuel system (fuel filter, fuel injectors or the pump), air intake system (air cleaner, throttle, and intake hose), engine management system (air flow sensor, oxygen sensor and camshaft sensor, among others) as well as the emission system components such as catalytic converters.

The use of a diagnostic computer will help zero in on the faulty component causing the emission system fault light.

WHY IS MY NOAH SLUGGISH AND WEAK WHEN DRIVING UPHILL?

Hello Paul, my Toyota Noah 2007 loses power and speed when driving uphill, even when I kick down the accelerator. Sometimes, it is sluggish and hesitates as if it is running out of fuel. What could be the cause?

Tiga

Hello Tiga, consider a diagnosis and inspection of the mass air flow sensor. This component monitors information about incoming air temperature and volume; both of which are used by the engine computer for altitude compensation (provide more engine power) as you drive uphill.

It is useful to inspect or test fuel delivery pressure, often delayed fuel filter replacement will reduce delivery pressure as well as damage the fuel pump. A clean fuel system is crucial for engine performance and prompt response to acceleration or demand for power.

X-TRAIL, RAV4 OR FIELDER: WHICH IS THE BEST?

Hello Paul, which of the above cars would you recommend? Please comment on maintenance and repair costs, fuel consumption, handling on the road and reliability.

Mathias

Hello Mathias, the first generation Nissan X-trail (2000-2007) and first generation Toyota RAV4 (1996-99) are highly competitive cross over sports utility vehicles. They are both tough as nails, versatile and easy to drive on road and light off road terrain. The X-trail and RAV4 both come from reputable stables, are practical and built to last. However, when compared, the X-trail and RAV4 have some differences, which set them apart, even further apart from the newer ‘kid on the block;’ the Toyota Corolla Fielder 2003.                    

Engine performance, fuel economy and maintenance: The T30 Nissan X-Trail’s 2.0 litre QR20DE engine delivers more power (138 horsepower) and better fuel economy (14km/litre) than the 2.0 litre RAV4’s output (126 horsepower) and fuel economy (11.7km/litres). The Nissan X-trail’s superior performance and economy are due to its multi-point injection, double overhead camshafts with variable valve timing.

The 1.8 litre Corolla Fielder provides less engine power (120 horsepower) but superior fuel economy (16km/litre) courtesy of its super select continuous variable transmission and engine variable valve timing. However, when these cars age (20,000 kilometres or 20 years on the road), the Toyota RAV4 proves to be easier and cheaper to maintain. The VVTi valve trains and chain-driven timing kits in the Nissan X-Trail and Corolla Fielder are sensitive to engine oil grade and quality. If not regularly maintained, they fail and are costly to repair. In the long run, the Nissan is more costly to maintain as it ages and requires more costly aging parts replacements.

Handling on and off road: The Nissan X-Trail’s longer and wider profile (width and wheel base) give it better road handling and stability during high speed manoeuvers on the highway. Off road, the X-trail’s auto selectable 2WD/4WD and higher ground clearance gives it prowess and can only be followed carefully, on murram roads, by the RAV4.

The RAV4 feels light on the highway while the Fielder is more settled at high speeds as it has the lowest centre of gravity.

Send sms: mycar (space) your comments and questions to 6933 or email them to: [email protected]

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