Virtual Mechanic

THE EFFECT
This type of problem will give the same affect as a blown head gasket.  It will cause the cooling system to appear unstable.  It may also cause the upper radiator hose to tear apart as the thermostat decides to open with a great force of hot water.

THINGS TO LOOK FOR
If you decide to put another radiator hose on.  What you  need to do is feel the upper and lower radiator hoses at normal operating temperature, very carefully, just in case the radiator explodes, and they should be almost the same temperature.  If one is cold and one is hot, this is an indication of a sticking thermostat.

COST
To replace the thermostat it will cost $30.00-$90.00 depending on the make and model of the vehicle and also depending on how old the vehicle is.  The thermostat housing bolts may break as you try to remove them.

PURPOSE
The fuse box is designed to hold fuses and relays and there may be several of these around the vehicle.  It’s always a good idea to keep a few spare fuses, just in case.

THINGS TO LOOK FOR
When checking the fuses, it’s best to check the fuses with a test light and don’t rely on the fuse index map indicating where the fuses connect as they may be incorrect.  What is meant by the map is that sometimes when you pull the fuse cover off  you have an index on what the fuses represent eg. wiper blades, wiper motor and you go to check that and it is not the wiper motor fuse.  The wiper motor fuse is in another location.  The most important thing is replacing the fuse with the same amperage.  Also the fuse may look okay but it may not be okay.  The only way to check or test a fuse is with a test light with the ignition on and the engine off.

IS IT EXPENSIVE TO REPAIR?
Replacing a fuse is an easy task if it is a low amperage fuse up to 30 amps but if it is a high amperage fuse it may require a 6, 8 or 10 mm ring spanner to remove it and repair it.  The most important thing to remember is if the fuse breaks when you replace it, it is showing a definite short in the system.  This needs to be attended to ASAP.  Putting a higher amperage fuse in will only load up the wiring and may lead to a more expensive repair as the wiring may melt or be damaged.

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

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PURPOSE
The fuel pump relay is designed to switch the fuel pump on with a low voltage.  At the same time the relay is a heavy duty switch making it possible to switch on and off without wearing out the switch or preventing arcing in the switch.  A fuel pump relay is designed to switch off if overloaded.

THINGS TO LOOK FOR
When the fuel pump relay seems to be getting warm to hot, this indicates that it is either being overloaded or becoming faulty.  A hot relay is a relay in trouble.  Apart from being hot it may show physical signs of slightly melting around the terminals.  This may be the effect of the cause and the suspect cause being the fuel pump overloading the relay.  If caught early this can prevent a breakdown.

IS IT EXPENSIVE TO REPAIR?
Changing a relay is easy but the cost may range from $8.00-$120.00.  Therefore it is important to check with your auto electrician to make sure it is the relay and not something else causing the relay to malfunction.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If your relay is a common type it may be swapped with an air conditioning relay as they should both be identical, specifically for common type vehicles.  A common type relay may be bypassed as a more complicated type may be bypassed by both but it’s worth trying.  If you want to swap the relays over, make sure that they’re of the same amperage.  You should see 30 amps or 60 amps or 80 amps. They’re both either the same quantity of terminals or voltage or amperage or colour.

 
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

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PURPOSE
The air flow meter is a component to allow the velocity of air through it and at the same time it measures the air passing either by a hot wire or a flap connected to a potentiometer.  This value is sent to the computer indicating the quantity of fuel required.  If the air flow meter is a hot wire type it also has a self cleaning process to keep the wire clean from the value interference.

THINGS TO LOOK FOR
The main thing to affect the air flow meter is the large ducting connected to the unit. Also any vacuum leaks will affect the air flow meter value.  A potentiometer may wear its contacts causing a possible flat spot or non start.  Its enemy is a backfire as this will twist the flap making it impossible to move freely.  A quick perusal will determine if the flap is twisted after a backfire thus requiring replacement.  The hot wire type may break, the wiring causing a non start.  The hot wire also has a self clean program.

IS IT EXPENSIVE TO REPAIR?
Either air flow meters are expensive to replace costing around $600.00 depending on the make.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
Most common types of air flow meters are now reconditioned costing around $300.00.  Make sure you keep your receipt in the Virtual Mechanic folder, as air flow meters do play up from time to time.

 
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

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PURPOSE
The purpose of coil and spark plug leads is to deliver high voltage spark from the coil to the spark plugs.  As ignition leads carry a high voltage it is very important to use caution when handling these leads with the ignition on or with the engine idling.  Ignition leads are made of fibres to reduce the possibility of radio wave interference.  Due to the high demand of these leads they may fail at any time. 

THINGS TO LOOK FOR
Ignition leads either deliver high voltage or they start to isolate and end up open circuiting thus creating a misfire.  This shouldn’t be ignored as a misfire may be causing damage to the exhaust system.  Also it may cause damage to the ignition coil as the high voltage can create a carbon track from the secondary lug to the primary lug destroying the coil.  A faulty lead may make the engine difficult to start.  All leads should be tested for resistance. 

IS IT EXPENSIVE TO REPAIR?
Ignition leads should be purchased in a set as they are replaced all at once.  When purchasing leads buy a well-known brand as even new leads can be faulty and testing is required before fitting to make sure that the leads are not faulty. 

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
Testing or fitting any leads must be carried out one at a time as ignition leads are designed to fire in a firing order.  For this reason it is best to remove and replace one lead at a time to prevent messing up the firing order, thus creating a potential backfire.

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

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PURPOSE
Air bags are designed to save lives and reduce the risk of personal injury to the driver and passengers. An extra $3,000.00 to purchase a vehicle fitted with an air bag is well worth the expense. If fitting any additional bumper bar component it may affect the air bag safety operation. 

THINGS TO LOOK FOR
Is it possible to see if an air bag is operating correctly or if buying a second hand vehicle fitted with an air bag?  The only way to check this is to take your vehicle to your mechanic and ask if they can access the fault codes on the air bag and this will show if it’s operating correctly.  Pay for this test procedure and get a receipt, with the fault code number, signed by the mechanic or the technician.  This way you have proof that the air bag is still there and is operating to its specification.

IS IT EXPENSIVE TO REPAIR?
Yes!.  Air bags are expensive. But so is your life!  If your vehicle has been involved in an accident with an air bag going off or when buying a second hand vehicle, make sure it is operating to its design purpose. The average air bag costs around $2,000-$3,000.00.

Mechanical configuration of linkages

 
PURPOSE
A mechanical configuration of linkages is to move the clutch lever fork.  A mechanical configuration is used instead of a hydraulic clutch applicator.  This is also adjustable.  A mechanical configuration may also use a cable that makes it adjustable.  Any clutch assembly must have free play.

THINGS TO LOOK FOR
A mechanical clutch configuration may require adjustment.  If you notice the pedal becoming hard to press this could be an indication of a frayed cable or a clutch assembly sticking.  As the pedal becomes harder to push this shows that it needs to be attended to ASAP.  A mechanical or cable clutch assembly may not tolerate a hard pedal and either snap the clip or rod.  When driving up hill if you notice the engine revs increasing but the speed doesn’t, the clutch assembly is slipping.  It either requires adjustment or the assembly itself needs replacing. 

IS IT EXPENSIVE TO REPAIR?
Most mechanical configurations use a cable assembly which costs between $60.00-$80.00 for the cable.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
A cable or mechanical assembly is best with 2-4mm free play.  A cable without free play will cause the clutch assembly to slip and rapidly deteriorate costing a lot more than the cable or cable adjustment.

 
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

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PURPOSE
The clutch slave cylinder is designed to plush the clutch lever in order to engage or disengage the clutch lever or fork.  The clutch slave cylinder has a bleeding nipple fitted  and bleeds the clutch hydraulic system.

THINGS TO LOOK FOR
The clutch slave cylinder is a component under pressure while it is in use making it possible to leak.  If there are any drops, or dampness is found around the clutch slave cylinder, it needs to be attended to ASAP.  The most common sign is a clutch pedal going to the floor and also there is difficulty in selecting gears. If you have to force a gear selector into gear this is the time to stop as the selector mechanism is a fragile component that will not tolerate the mechanisms being forced.

IS IT EXPENSIVE TO REPAIR?
The clutch slave cylinder is repairable but not if the bore is scored then it needs to be replaced, costing between $50.00-150.00.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
It is possible to repair the clutch slave cylinder especially if it is made of cast iron but check the bore.  If the bore is scored it may be better replaced.  The clutch slave cylinder will need to be bled after being installed.

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

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PURPOSE
The carburettor is a very important multi function component as it mixes air and fuel together and it allows the engine to idle, to rev and to maintain desired speeds and overtake on full throttle.  At the same time its purpose is to mix air and fuel at the correct ratio.  The carburettor is only designed to operate with clean fuel and must be mounted securely in the manifold. 

THINGS TO LOOK FOR
The carburettor is capable of leaking fuel.  Signs of dampness or of red colour are indications of this.  Any fuel leak or smell must be attended to A.S.A.P.  A carburettor is also capable of blocking up the cruising, idle or full throttle circuits.  All these circuits are linked to a fine orifice or emulsion tube.  A flat spot or an automatic choke staying on for too long, indicates a problem circuit but the most dangerous indicator is a sticky throttle as this may cause an accident.

IS IT EXPENSIVE TO REPAIR?
Carburettors are costly, ranging from $85.00 for a single barrel to $350.00 for a four barrel.  Fuel over the years may gum up the operation and this is time to have the carburettor serviced.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
A blocked carburettor may go away or it may stay and require mechanical attention.  One option is sucking the problem out with a rag but be very careful as anything with fuel is dangerous and you can risk a backfire in your face or risk damage to your skin.
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

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PURPOSE
A brake warning lamp may be a handbrake light, a master cylinder level indicator or a master cylinder losing excessive fluid which enables the switch to be activated.

THINGS TO LOOK FOR
The most serious light indicator is a brake light staying on because the system is leaking excessive fluid.  The first step is to check the fluid reservoir.  If it’s exactly at the full mark while you have the cap off, push the level indicator down to see if the light goes out.  Also check the hand brake lever to see if the light fades or goes out if you manipulate the on and off on the handbrake.  If either works, disconnect the connection to the master cylinder.  If the light goes out have your mechanic inspect it before you drive it anywhere as the light connected to the master cylinder, the warning brake light, is a brake fluid loss indicator.  This is a serious problem.

IS IT EXPENSIVE TO REPAIR?
Costs may vary, depending on the source of the problem.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
Disconnecting the warning lamp to prevent the light from coming on is not the way to go as it’s designed to prevent the brakes from failing.

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

Join the forum discussion on this post - (1) Posts