Car Care: Squeals should not be ignored

Make sure all necessary steps are taken to ensure nobody can try to turn the engine over while your head is under the bonnet and hands are touching or within reach of the drive belts. Photo / GettyImages

Problem may not be as expensive to fix as it sounds but left too long could make vehicle unsafe

I'm sure we have all heard that horrible high pitch squeal emitting from under the bonnet of some vehicles as they pull out of driveways or parking spaces.

The squeal usually slowly reduces and finally disappears as the engine/vehicle speed increases. It definitely sounds abnormal and very expensive to fix, which is why I suspect some owners simply turn the volume of the radio up and try to pretend it isn't there.

The reality, however, is the squeal may not be as big, or as expensive, a repair as some would imagine. Also, on the positive side some quick and simple quick self-checks can help pinpoint the problem fairly quickly without the need to engage the services initially of a trained technician.

On the downside, if left unattended, the end result could lead to additional repairs and costs, but more importantly in a worst case scenario can potentially and very quickly make the vehicle very unsafe on the road.

The noise is usually caused by a slipping external drive belt (should not be confused with a cambelt).

Just which drive belt is the culprit is often the big question and one which can cause confusion for many home mechanics.

Many vehicles are fitted with a number of external belts to drive components such as alternators, water and power steering pumps, plus air-conditioning compressors, so it can become something of a hit and miss affair to identify where the noise is actually coming from.

To help make things easier, one quick and easy step is to try and firstly eliminate the air-conditioning belt.

Check to see if the A/C is switched on (in-cabin A/C button should be illuminated). If it is on, then switch it off, to reduce the load on both the compressor itself and the drive belt. If the squeal goes away then you have successfully identified the problem.

The belt will then need to be closely inspected for excessive wear and correct tension. If the squeal is still present then lightly spray water over the remaining belts with the motor running to see if the noise goes away temporarily.

A garden hose or spray bottle is advised to ensure hands and any loose clothing do not get too close to any moving parts in the engine bay.

Checking the condition of any of the drive belts is often harder than it sounds, so once again some safety precautions are advised. Most important is making sure all necessary steps are taken to ensure nobody can try to turn the engine over while your head is under the bonnet and hands are touching or within reach of the drive belts.

A bright light is also advised to help check drive belt condition. Replacing and/or tensioning any of the drive belts can at times be fairly involved and may need the expertise of your referred repairer to ensure it's done properly (for example you may be surprised at just how much tension is required on an A/C belt).

So what are those safety risks we mentioned if the belt squeal was allowed to continue for too long?

Well let's assume it is the A/C belt causing the squeal due to wear or lack of tension. If left, then ultimately it could break, causing parts of the broken belt to potentially get tangled up with other moving components such as the power steering or alternator drive belt.

If the power steering belt were to suffer damage and stop driving the power steering pump without any warning to the driver, then potentially the car suddenly becomes very unsafe on the road.

Without the assistance of power steering, vehicles become almost impossible to steer.

Not all vehicles have external power steering pumps or drive belts these days but regardless of what belt configuration is used on a particular make/model high pitched squeals should not be ignored.

For older vehicles, or where there are financial restrictions, a temporary solution can be as easy as leaving the A/C switched off while in some other cases it may only mean a tightening of a particular belt's tension.