Why does my petrol car sound like a diesel car?

I drive a Nadia 1999 that has a wonderful speed and performance but its problem is with the way the engine sounds. It’s like a diesel engine car yet it’s a petrol engine. What could be wrong with my engine?
Secondly, it has a problem with the ignition. I thought it was because I hit a speed bump and up to now I have failed to get right fuel pump for it. Kindly, I request for your help.
Solomon.

Your concern about the new sound in your car engine is justified. Cars, like people, communicate when something is wrong.
All cars make some sort of noise, which is characteristic of their performance and is familiar to the driver.

When a car engine develops an unusual noise, it may be caused by a simple misfire or expensive wear and tear of the fast moving metallic components. In your case, your petrol engine has a rattling sound typical of a diesel engine.

Without the benefit of listening to your engine, I can only rely on your description. Here are some common engine sounds and their causes that you can discuss with your mechanic:
Rattling and ticking as you accelerate are often caused by retarded or advanced (wrong) camshaft timing, engine valves or tappets which need adjusting or are running dry without sufficient lubrication due to thick sludge build up.

Popping sound and engine hesitation is characteristic of dirty spark plugs, clogged fuel filter, damaged or faulty fuel pump (in your case its attached to fuel gauge and you have failed to secure the right one).

Deep knocking sounds as you accelerate are typical of crankshaft to piston ring damage that cause a loud piston slap. This is often a result of use of wrong or counterfeit motor oil.

Squealing or whining noise will either be a worn out or fan belt or engine camshaft timing belt. Hissing is typical of an overheating engine.
To secure the right pump visit the Toyota Uganda or any genuine Toyota parts dealer.

Do I need a thermostat?

Hi Paul, Immediately after buying my Premio 1998, l headed for first service. The service-man told me to remove the thermostat because it would be causing my engine to overheat. That it is meant for driving in the cold countries but not for hot regions in the tropics. He removed it and l have been driving without it. Should l put it back or stay without it.
Michael.

It is important to replace your Toyota Premio car’s engine cooling thermostat with a good quality part when it fails or as a precaution at 100,000kms. A thermostat will fail due to age or exposure to corrosion resulting from delay to renew the coolant fluid. This will lead to engine over heating as the thermostat will fail to allow coolant to flow from the radiator to the engine.

It would be prudent not to re-use the old thermostat because it has been exposed to the elements and probably suffered from corrosion damage. A new one is not expensive and can be bought from any genuine Toyota parts dealer in town.

Remember to replace all coolant fluid in your engine once every two years with a good quality product with corrosion inhibitors and a chemical lubricant to protect the water pump.

I have a Toyota Fielder, its pick-up speed is a bit slow but after pickups it is all okay. What is wrong?
Charles M.

Hello Charles, when you say ‘pick up speed’ I imagine you mean acceleration. In simple terms acceleration of your car is the rate at which you increase its speed in a particular direction. There are factors which will affect your Corolla Fielder’s acceleration such as torque, power, gearing (transmission), handling as well as the design or vehicle load. Your Fielder comes with small engine sizes either the 1.5 or 1.8 litre options.

These engines and their transmission are designed to deliver very efficient performance (good fuel economy and engine power at low or high end engine revolutions. A multi role family transport solution. It is not a rally type vehicle hence the small engine and transmission design. No wonder it accelerates even slower when you are carrying five passengers and their luggage.

Failure to maintain the engine by renewing the fuel filter, spark plugs and air filter periodically will reduce the engine torque and affect acceleration. Confirm that the gearbox oil service is up-to-date. A poor response of the automatic gearbox affects acceleration. You need to ask your mechanic to inspect the car.

Hi Paul,
thanks for the educative work you are doing. I own a Toyota RAV4 first generation with a manual transmission. After reading your articles over time I have observed that you emphasise that the good performance of an engine will depend on many factors, which include the type of engine oil and service parts used. To a layman like me oil is oil.

What exactly should I be looking for in the oil that I put in my car and what type should I use? In Kabale where I live, whichever service station I go to they give me a different type of oil and tell me that it is better than all the others. I am considering going for my next service but I am skeptical. Please help.
Anonymous

Hello, engine oil plays a major role in the maintenance and protection of your engine. The engines in the post 1990 vehicles are very sensitive to sludge, deposit and corrosion formation. These engines demand more than just lubrication from the engine oil you choose. You ought to select engine oil which is blended with special additives that prevent sludge build up and keep it in suspension to carry away after burn deposits for filtration over the drain interval.

Good engine oil should be designed with corrosion inhibitors to prevent rusting of the frequently heated and cooled metallic engine components.

Good engine oil is designed to help cool the engine while its detergent additives keep the internal components clean and free of deposits. You can find these attributes in the whole range of Shell motor oils. Identifying the correct engine oil for your RAV4 requires consulting your user manual or in its absence the Toyota dealer. At Toyota Uganda they recommend motor oil viscosity grade 15W 40.

These numbers can be seen on the motor oil can and represent the viscosity, simply the ability of oil to flow. The number before W indicates that this oil will maintain its viscosity when run in an engine at cold (sub zero) temperatures below minus 15 degrees centigrade. The number 40 represents the upper temperature limit at which the oil will maintain its viscosity when heated up.

When you look at the oil container, you should be able to see the classification ‘S’ which represents ignition by spark for petrol engines. There are 15W40 oils designed for diesel engines with classification ‘C’. The 15W40 multi grade viscosity is often better and safer for your engine than the monograde (SAE 40) because it covers a wider temperature range. I would recommend you use the Shell Helix HX5 15W40.

This motor oil meets the above standard and carries all the above attributes necessary to maintain and protect your engine while keeping the environment clean. This Shell lubricant is readily available all over the country and at the nearest Shell station in Kabale.

Ask the mechanic, call: 0772316145