Need to describe the noise

Q1: My 2004 BMW E46 3 Series has 48,000km on the clock. When cold-started, the noise from the engine compartment is quite loud for about two to three minutes before it quiets down.  Is this normal or should I be worried?

LH
Penang

Your question did not specify the kind of noise coming from the car. If it is a squeaking sound, it usually indicates that the problem lies with the drive belt. If however your engine is using a timing chain and sprocket, then the noise is quite normal. For peace of mind, get your service centre to pinpoint the exact source of the noise and resolve it if necessary.


Q2: The car in question is a 2004 Nissan Altima. When rotating the steering wheel and some times on putting the car into reverse, there is occasionally a one-time clicking or “clunking” noise. There is also a clicking sound when I hit the brakes. The workshop I sent my car to concluded the car needs a new control arm. What do you think?

Altimate
Muar

The lower arm bushing in your car is one of the most common parts to be damaged. The whole lower arm will only need to be changed if it is deformed. Otherwise, it is sufficient to just change the bushing or the ball joint of the lower arm. 


Q3: I have been introduced to so-called magnetic fuel energiser products that are said to result in better fuel-air combustion. But I suspect these are just snake oil or pseudo-science. Will using such products cause engine damage?

D. Amafi
Kota Baru

First of all, if this so called magnetic fuel energiser is not part of the Original Equipment Manufacturer (OEM) parts already pre-installed in your car, it means it is not a compulsory item to be fitted to your car.

According to some magazines, the use of a magnetic fuel energiser prevents carbon deposits that usually builds up during the burning of the fuel. Whether that's true or not is debatable.

Verify with your car manufacturer whether using the aftermarket product is safe, then weigh the pros and cons of using it.