Retard ignition timing

Q1: I'm currently driving my father's 1976 Toyota Corolla KE50. To prevent knocking, the car had been using RON97 for years. As the price of RON97 is high now, and nothing says I can't use RON95, I'm planning to downgrade. Is it safe to do so?

Young Corolla Driver
Penang

Just retard the ignition timing on the KE50 engine and you are done. If the engine has Exhaust Gas Recirculation (EGR), check the EGR valve to see if it is working properly.

Basically, the EGR lowers combustion temperature and is a means to prevent detonation.

For 1976 Toyota Corolla KE50, switching from RON97 to RON95 petrol doesn’t have any significant impact. So go ahead and switch.


Q2: I’m using a 2009 Proton Exora  with auto transmission.

I have been using it for outstation trips lately. While driving on the highway, the car emits a humming sound from the left front passenger side. It is more audible once the car is speeding at over 130kph. This happens no matter if I drive straight or cornering.

The sound gets louder when I increase the speed.

The car is 1 1/2yrs old but only has around 22,000 mileage. It's a family car uses only on weekends and during family outings.

Whats seems to be the problem?

Wilson.T
Kuala Lumpur

The humming sound sounds like the wheel bearing is worn out or damaged. It can also be caused by tyre tread condition or the state of the road surface. Your Proton service centre should be able to troubleshoot the problem and change whatever is necessary.


Q3: I'm the second owner of a 2010 MINI Cooper S. It had clocked 6,500km at the time of purchase. There was a whirring sound whenever the car engine is started and continues on. It sounds like an electric car. It doen’t affect the car’s performance as fast as I can tell. The MINI mechanics say it’s nothing to worry about. But I have tried earlier MINIs and they don’t have this whirring sound.

Is there any reason to be worried?

MINI Gurl
Skudai

The whirring sound is caused mainly by worn-out bearings or bushings, such as the alternator bearing, power steering pump bearing, air-con compressor, timing drive tensioner and water pump bearing.

Additionally, It could be the sound of the supercharger mechanism. The moment the engine starts, the supercharger also starts to operate and that sound actually comes from rotating parts of a Roots-type supercharger.

A process of elimination must be done to identify the real cause of the whirring sound. Have it checked by an experienced technician.