Virtual Mechanic

Virtualmechanic Darren Gow-Brown free online video is explaining checking the brake Fluid is vital to prevent breaking down on the side of the road.

PURPOSE
The tank is designed to store liquid gas, and depending on the country, may come in many different shapes and sizes, providing different capacities.  An LP gas tank is checked before it is sold and is best checked every ten years for leaks or wear.  Gas tanks are designed to hold eighty percent of their capacity to allow for expansion.

THINGS TO LOOK FOR
An LP gas tank may be checked with warm, soapy water for leaks as well as dents.  It is important that the tank is positioned correctly to allow the gauge to maintain an accurate measure of the liquid gas inside the tank.  Tanks must be secure and the gas tap must be easy to turn on and off. 

IS IT EXPENSIVE TO REPAIR?
If a gas tank requires replacement it’s best to purchase a new tank or a reconditioned tank as this will show a certified ticket to ensure it is a safe tank to use.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If the gas tank appears to be leaking, turn the gas tap off and take it to a qualified gas installer for a check up.

PURPOSE
The petrol solenoid is designed to allow petrol through it when energised, may be applied when starting  up the vehicle on gas.  Some vehicles fitted with electronic fuel injection may automatically start up on petrol, then when the rpm reaches 2000 the engine will switch over to gas.  Therefore it is important to keep at least a 1/4 tank of petrol for this reason.

THINGS TO LOOK FOR
Petrol solenoids are only as good as their connections.  Petrol solenoids are usually mounted to a heater hose or are just freely connected to the fuel line making it very important for the earth and the positive to have enough slack to move with the solenoids.  So when you rev it, the engine moves and so will the solenoid.  A common problem is the connections become loose or the terminals are just crimped and not soldered then it is just time before the petrol solenoid will not operate.

IS IT EXPENSIVE TO REPAIR?
If you know how to solder terminals, this is the cheapest way.  Otherwise visit your local mechanic or auto electrician.  The cost is around $30.00 to solder a few joints.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If it seems to be impossible to get the power to energise the petrol solenoid and you just want to drive to your local repairer then carefully connect a fuse wire from the battery to the petrol solenoid to drive it on gas.

PURPOSE
The gas adjustments are calibrated best by the use of a Dynometer as this will provide the most accurate measure of torque thus maximising the fuel economy.  There are basically three adjustments to be made on any gas system.  They are idle, cruising and full throttle.  The idle should be the only one requiring adjustment and the full throttle and cruising adjustment are best performed on a Dyno by a qualified gas fitter, preferably every 10,000Kms.

THINGS TO LOOK FOR
Heavy fuel consumption is one indication that the gas system requires adjustment.  Most gas vehicles can be running too rich.  Another indication is a lack of power.  These two problems are difficult to rectify but if your engine idles rough check that all the rubber ducting is in order and well secured.  A sign for running rich or running rough is a dirty air cleaner.  Be sure that it is not blocked or built up with dirt.  After checking all these components, the last thing to do is adjusting the idle, but remember where you started as this may make no difference so if it doesn’t return the adjustment, screw to the original position

IS IT EXPENSIVE TO REPAIR?
A good Dyno tune may cost around $95.00 and a good Dyno tune should improve your vehicle’s performance and economy.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
There is only one temporary adjustment and that is the idle.  Other than that, the adjustments will affect the vehicle’s performance and the emissions entering the atmosphere.

PURPOSE
Welsh plugs are part of the engine block and the head.  When the engine block and head are manufactured, part of the casting process is that these parts have the welsh plugs fitted where the machines are able to enter and then when the casting is finished a welsh plug is fitted to seal off the cooling or oil system.

THINGS TO LOOK FOR
Welsh plugs can leak at normal operating temperature.  When this happens, stop the engine and get the vehicle towed to the garage.

IS IT EXPENSIVE TO REPAIR?
Nearly all welsh plugs are expensive to repair as they are hard to get to.  The welsh plugs themselves cost only a few dollars each but the labour is the expense.  Welsh plugs are either made of brass or steel, cup or dish.  It is best to consult your motor reconditioner to work out which is the best one to fit.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If a single welsh plug is found to be leaking it may be a consideration to get all the welsh plugs replaced at the same time.  It really depends on how long you intend to keep the vehicle.  Once any welsh plug is replaced, always change the water and add corrosive inhibitor on a regular basis, eg every 12 months or 10,000-20,000Kms.

PURPOSE
The water recovery bottle is designed to recover expanded water and store it and when it has cooled down, the water flows back into the radiator.   Check radiator and the water recovery bottle at the same time. It is best checked when the water is cold. 

THINGS TO LOOK FOR
The water recovery bottle is part of the cooling system.  For this reason caution should be taken when checking the levels as the bottle, if warm, is under pressure.  The best way to completely check the cooling system level is when the engine is cold.  Radiator and water recovery bottle are best to be checked at the same time.  If you need to top up the water level when the engine is warm or hot use caution, as hot water will cause severe burns.  When opening the radiator cap use gloves or a rag or a radiator protector opener.  When filling the radiator or water recovery bottle, leave the engine running as you fill the radiator.  This will prevent the cooling system from any damage to the head.

IS IT EXPENSIVE TO REPAIR?
Replacing the water recovery bottle is around $30.00.  But try to work out why the bottle needs replacing as it may be a repeat situation which may be caused by a cooling system fault.

PURPOSE
Water is designed to maintain normal operating temperature.  Water will only perform this function if all other components are operating correctly.  Water should include an additive to prevent corrosion and erosion.  If your vehicle is driven in either a very cold or very hot climate it may be necessary to add either an anti freeze or anti boil solution.  This will only work effectively if the corrosive inhibitor is changed every 12 months.

THINGS TO LOOK FOR
The colour of the water tells a very good story about the condition of the cooling system.  Brown water is the worst, clear water is not good; green water is best and it needs to be changed every 12 months to keep the colour at its best.

IS IT EXPENSIVE TO REPAIR?
If your vehicle is pre 1990 then a good corrosive inhibitor, eg Castrol, may be okay.  If it is after 1990 then contact your dealer as the seals and welsh plugs require specific inhibitors to protect these components.  These additives may be expensive.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If your vehicle has brown water, disconnect the heater hose and remove the radiator cap and secure a garden hose in the heater hose and turn on a moderate pressure.  This is the best way to reverse flush the cooling system.  Please note: this should only be done when the engine is cold.  It may require several applications until the water runs clear.  It is a good idea to turn the heater tap as this will also flush the heater core, in case it might be partially blocked.

PURPOSE
The viscose fan is attached to the water pump and designed to cut in and out depending on the temperature of the water.  The fan will last at least 5 years or 100,000Kms.  After this the fan should be checked periodically every 10,000Kms for its effectiveness.  The viscose fan is a fluid substance that changes its viscosity depending on the heat, allowing the fan to freely move or lock up on a one to one ratio with the pulley.

THINGS TO LOOK FOR
A viscose fan should cut in and out, if monitored over 1/2 hr of the engine idling.  Use extreme caution with the viscose fan or any fan blade when checking.  The best way to check the fan is to idle the engine for about 1500 revs per minute to 2000 and you will notice when revving the engine while hot, more of a fan noise will be apparent.  Then when the cooling system cools down the viscose fan is not consuming any energy from the fan belt or water pump pulley.  A viscose fan may also cause the engine to overheat at moderate to high speed.

IS IT EXPENSIVE TO REPAIR?
Viscose fans may be expensive to repair depending on the make and model.  It’s always a good idea to replace a viscose fan with the original type.  They could cost around $150.00.  Getting one from the wreckers is not recommended as most of these fans are faulty.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If you are stranded and the fan is locking up, cooling the radiator, then you can try overhauling the viscose fan and putting a bolt in to prevent it from free wheeling just to get you around.  But it does affect your fuel economy.

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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