Virtual Mechanic

PURPOSE
Alloy rims are beneficial to the braking system as they allow a faster cooling down period.  Most alloy rims should last the life of the vehicle if driving on sealed roads.  Alloy rims should be fitted with the correct wheel nuts with one of those being a locked nut.  They are very popular but they are expensive, not repairable and can affect your insurance policy. 

THINGS TO LOOK FOR
A dented alloy rim is easily detected and better replaced as it may continue to deflate.  If your vehicle is fitted with an alloy rim , make sure you always keep the locked nut of the alloy rim in a safe place as it makes it easier if you breakdown.  Sometimes people keep their locked nuts in a spot where they cannot find it.  If your vehicle is fitted with four alloy rims and a spare that is a steel rim, make sure the wheel nuts will fit the spare in case of a wheel replacement on the side of the road, as some wheel nuts won’t fit the steel rim.  This makes it very dangerous to fit a steel rim with the wrong wheel nuts.

IS IT EXPENSIVE TO REPAIR?
The only way to repair an alloy rim is to replace it.  You may be lucky to get one at the wreckers otherwise you will have to buy from a retail outlet.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If your rims are hard to get or very expensive and you decide to leave the steel rims on for a while, be very sure that if on the front, both tyres are the same make and the same pattern, to maintain the same braking reaction for both tyres.  The same applies for the back tyres.  Also the differential can be affected if one tyre is a higher profile and one tyre is a lower profile.  Basically what we are saying here is that all tyres should be the same profile and the same type.  The rims can be different, providing the steel rims are able to be secured with the same wheel nuts. The profile will affect the braking and any different type pattern on the front or back,  or different size on the front or back,  will affect the braking force and that’s an unroadworthy item.  For a roadworthy vehicle all tyre patterns on the front and back should be the same.
This article is found in the Virtual mechanic CD Rom
You can download it for the price of a latte, but you will learn not to buy a lemon
By Darren Gow-Brown, Melbourne Australia ©2009

PURPOSE
The air valve, idle control valve or stepper motor all have one thing in common.  They are designed to maintain a smooth idle by manipulating the air supply to the air inlet manifold and are computer controlled.

THINGS TO LOOK FOR
The air valve, over a period of time, may clog up and may cause the engine to idle poorly and the stepper motor may stop stepping.  If the stepper decides to cause the engine to idle at around 2,000 RPM, another component could be causing the computer to control the stepper motor to idle at an incorrect setting.  Another poor idle problem is the air ducting or air hose attached to the inlet manifold may be off or loose.

IS IT EXPENSIVE TO REPAIR?
If the vehicle is running rough, a thorough check may show a vacuum line off.  It will be an audible whistle sound and it should be easy to see.  Sometimes these are in tricky locations and may take time to find.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
This is quite simple as 80% of the time it is just a matter of slipping the hose back on.  If the problem repeats itself then it may be necessary to clamp it up or replace the vacuum line.

This article is found in the Virtual mechanic CD Rom
You can download it for the price of a latte, but you will learn not to buy a lemon
By Darren Gow-Brown, Melbourne Australia ©2009

PURPOSE
The air cleaner assembly contains the air cleaner and it’s also designed to arrest a possible flame from a backfire.  The original air cleaner assembly is the best flame arrester as an after market air cleaner may not be designed to flame arrest a possible backfire.  It may cause an under bonnet fire.

THINGS TO LOOK FOR
If you are purchasing a second hand vehicle check that the air cleaner assembly is the original as this design will prevent an under bonnet fire from a possible flame caused from a backfire.  The same applies when choosing another air cleaner assembly or modifying the original.  It must be kept original for its design purpose to arrest flames if a backfire should occur.

IS IT EXPENSIVE TO REPAIR?
If you have purchased a second hand vehicle with a non original air cleaner assembly then you may try the wreckers and for around $30.00 you should find the original type of air cleaner assembly.
This article is found in the Virtual mechanic CD Rom
You can download it for the price of a latte, but you will learn not to buy a lemon
By Darren Gow-Brown, Melbourne Australia ©2009

PURPOSE
An air cleaner element cleans or filters the air before it enters the carburettor.  This prevents any damage to the combustion chamber. The air cleaner element should be checked and cleaned every 10,000kms.

THINGS TO LOOK FOR
The obvious is a dirty air cleaner element.  Another filter inside the air cleaner assembly is a positive crank case ventilation valve filter pad that should also be checked.  If clogged, soak in kerosene or replace if necessary.  Another common problem is oil around the base of the air cleaner assembly.  This indicates blowby, which means that the oil rings are clogged or worn.  Go to oil rings to find out more about this problem.
IS IT EXPENSIVE TO REPAIR?
A good air cleaner is around $18.00.  There are many types on the market but it is always best to go for a well-known brand.

 
This article is found in the Virtual mechanic CD Rom
You can download it for the price of a latte, but you will learn not to buy a lemon
By Darren Gow-Brown, Melbourne Australia ©2009

ENGINE
Rear main seal

PURPOSE
The rear main seal is at the rear of the crankshaft, sealing the oil inside the engine and preventing it from leaking outside the rear of the crankshaft.  The rear main seal is designed to last at least 100,000Kms.  Unfortunately, with a longitudinal motor, rear main seals may only last 60,000-80,000Kms.

THINGS TO LOOK FOR
When checking for oil leaks it’s always good to check underneath the vehicle around the rear of the engine.  But make sure it is around the rear main seal and not around the top of the head.  Sometimes a leaking rocket cover gasket may be the cause, if after replacing the rear main seal, there is still oil leaking.  The best way to check any seal is to give the engine a complete steam clean but be very careful not to spray the steam around any ignition component or carburettor as this will affect the ignition system and also may cause a non start.

IS IT EXPENSIVE TO REPAIR?
The rear main seal itself costs around $15.00 but the labour is around $350.00 as it can be a full day’s job with some vehicles because either the engine or the transmission has to come out to replace the seal.  Some rear main seals may cost $1000.00 depending on the type of seal fitted.  It may be a sealed unit or a wick seal.  A wick seal is the worst seal because it is very difficult to fit and to ensure that there is no leaking.

Most people are familiar with the conventional “SLI” ) Starting, Lighting and Ignition) lead-acid battery which delivers the high amp energy necessary to provide maximum starting power.  Once the engine has started, the alternator recharges the battery.  However, repeated cycling, as well as the continual process of discharging and recharging, eventually weakens the :SLI: battery which provides concentrated starting power, the deep cycle type battery supplies a constant but relatively low amount of current for a long period of time when an extended power supply is preferred.

Battery technology covers every automotive need from original equipment for Australian manufactured vehicles to batteries designed to suit specialised requirements.

This article is found in the Virtual mechanic CD Rom
You can download it for the price of a latte, but you will learn not to buy a lemon
By Darren Gow-Brown, Melbourne Australia

In addition to providing the starting power required, the automotive battery also supplies power to accessories such as lights, fans and radio when the engine is not running.  Between low engine speeds and when accessory load is greater at high running speeds, a battery makes up the difference by stabilising the alternator output.

This stabilising effect also protects a vehicle’s electrical system by smoothing out sudden high voltages which can damage electrical components.

Ask the average battery purchaser this question and most would say that a battery is simply the source of power necessary to start the engine of every motor driven vehicle.  Since most purchases are unplanned for, consumers usually have little knowledge or understanding about one of the most vital components of an automobile – the very essence of its electrical power.

With the increased demand of today’s technologically advanced cars, a basic understanding of the automotive battery, how it works and how to maintain it to ensure maximum performance and safety has become more important than ever.

The automotive storage battery falls under the category of a secondary battery.  Secondary batteries are rechargeable, unlike a primary battery which is not rechargeable and used to power devices such as flashlights and transistor radios.

This article is found in the Virtual mechanic CD Rom

Batteries what are they ?

Appears as “spotted” deposits on the firing tip of the insulator and often occurs after a long delayed tune-up. By-products of combustion may loosen suddenly when normal combustion temperatures are restored. During hard acceleration these materials shed from the piston crown or valve heads, and are thrown against the hot insulator surface.

More information On Basic Car Maintenance CD Rom
Information supplied by Champion Sparkplugs ©2009

Usually one or a combination of several engine operating conditions are the prime causes of pre-ignition. It may originate from glowing combustion chamber deposits, hot spots in the combustion chamber due to poor control of engine heat, cross-firing (electrical induction between spark plug wires), or the plug heat range is too high for the engine or its operating conditions.

More information On Basic Car Maintenance CD Rom
Information supplied by Champion Sparkplugs ©2009