Archive for the ‘Cooling System’ Category.
October 1, 2009, 19:01
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.
October 1, 2009, 18:59
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.
October 1, 2009, 18:57
PURPOSE
The water pump is designed to circulate water around the cooling system when required. The water pump is usually driven by a pulley that’s connected to a fan belt and it may also have a fan blade attached to it. The water pump is usually cast aluminium and designed to operate under a temperature parameter of 13-16 lbs per square inch (psi) at normal operating temperature.
THINGS TO LOOK FOR
A water pump, over time, may start to leak at normal operating temperature or it may leak several hours after being switched off with no or low pressure. These are signs not to drive the vehicle and replace the water pump ASAP. The bearing inside the water pump may fail causing the water pump seal to leak. This is an urgent sign that it needs repairing as the pump shaft may end up towards the radiator causing more damage to the cooling system. If the shaft bearings collapse then the whole shaft may move away from the water pump and end up with the fan in front of the radiator.
IS IT EXPENSIVE TO REPAIR?
Replacing the water pump may be expensive if the pump is connected to a timing bell or behind several brackets, it could cost up to $300.00. But if it’s an easy water pump to get to it may only cost around $150.00 provided that no bolts snap and some bolts may be corroded. The cost will also vary depending on the make and model of the vehicle.
TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If a water pump is leaking from a pin hole then it may be welded but this could affect the seals as it’s being welded. But it’s worth a try if the pump costs around $300.00.
October 1, 2009, 18:55
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.
October 1, 2009, 18:53
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.
October 1, 2009, 18:52
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.
October 1, 2009, 18:50
PURPOSE
The thermo fan switch when it reaches its designed temperature is designed to switch on and when it reaches a lower temperature, it is designed to switch the power off. The thermo fan switch receives power from the fuse box. When it reaches a temperature the switch will bridge the terminals thus turning the thermo fan on.
THINGS TO LOOK FOR
Check that the connections are secure and observe that the thermo fan is switching on and off. Sometimes this may not occur and just manipulating or wiggling the terminals may cause the fan to switch on. If this is the case then take the terminal off and clean it and refit it. Otherwise replacing the switch might be another option.
IS IT EXPENSIVE TO REPAIR?
A thermo fan switch is a costly item at around $60.00-$90.00. It’s better to buy the same type of switch as the original.
TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If stranded the switch may be bypassed and the terminals bridged, but remember this will put a load on the battery and will always turn the fans on when the ignition is turned on. Or on some vehicles, if you bridge the terminals it may stay on indefinitely.
October 1, 2009, 18:48
PURPOSE
The thermo relay is a heavy duty switch to prevent the request switch from overloading with excessive current or heat.
THINGS TO LOOK FOR
As the thermo fan operates over years the internal mechanisms may start to wear and cause a resistance in the thermo fan relay causing an overload on to the relay and the fuse. A common sign is a faulty relay. Melted terminals on the relay indicate that the thermo fan may be overloading the system or drawing too much current caused by an internal fan problem.
IS IT EXPENSIVE TO REPAIR?
If it is a standard thermo relay it may cost around $20.00.
TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If all other relays are the same specs, ie they may have 30 or 60 amps, make sure that the thermo fan relay is the same as the other and then just swapping the relay with another just to get you home if you’re stranded.
October 1, 2009, 18:45
THE EFFECT
The cooling system will maintain normal operating temperature under all driveable conditions.
THINGS TO LOOK FOR
It’s always a good idea to look at the thermostatic fan to understand how it operates. Because thermostatic fans are thermostatically controlled and they should switch on and off. A good thermostatic fan in a very good cooling system will switch on for somewhere between 20-40 seconds. If the fan switches on for longer than 60 seconds this might be a cooling system that is unable to cool down with the thermostatic fan. Another problem might be associated with the cooling system. If the fan stays on for 5 seconds, this is an excellent cooling system as it never requires a lot of effort from the thermo fan.
October 1, 2009, 18:43
PURPOSE
The thermo fan fuse prevents the wiring or the motor from melting from a short circuit.
THINGS TO LOOK FOR
Fuses don’t just blow for no reason at all, they blow when they are overloaded. If a fuse is blowing as soon as you put it in, you need to have an auto electrician check it out. It shows that there is a definite short in the system causing the fuse to blow.
IS IT EXPENSIVE TO REPAIR?
Replacing a ceramic or glass fuse is inexpensive. A good idea is to carry a few spare fuses in your vehicle.
TEMPORARY REPAIR AND LONG TERM REPLACEMENT
It is usually a 15-20 amp fuse. If you try a 25 amp fuse and it blows go no further but remember if you have air conditioning turn it on as it may switch on an additional fan and drive at least 60Kms. This will also keep the engine cool.