The cooling system of your Volkswagen vehicle is an important part in order to keep your vehicle operating efficiently. The cooling system maintains the right temperature of your engine through the circulation of coolant through the engine that picks up heat and passing it through the radiator where it is cooled with air. The coolant in turn passes through a thermostat valve to control flow and through a temperature sensor which controls external air cooling fans.
Volkswagen vehicle cooling systems are comprised of three main parts and these are the VW water pump, VW hoses and VW thermostat, radiator and sensors.
Volkswagen Water Pump
The VW water pump handles the VW’s cooling system’s pumping function which keeps the coolant mixture moving. The basic VW water pump is gear or belt-driven there are also some cases in other cars wherein a secondary electric water pump is used to improved cooling and flow of the coolant mixture. One of the most important parts of the pump’s operation is the drive belt which is also known on most new cars as the timing belt. However, on older car models, the pump and the belt are external and run off the main crankshaft pulley using a “V” of flat belt.
The maintenance of VW water pump is done simultaneous with the replacement of the coolant, the drive belt and tension adjustment (external type). The timing belt driven pumps should always be done when replacing the timing belt and tensioner.
The VW cooling system involves various hoses which includes the Volkswagen radiator hose, control valves, the heater core and the expansion tank. And since these materials are constantly used and are exposed to heated coolant, these parts deteriorate easily and needs to be change more often.
The maintenance of cooling system piping consists of scheduled replacement of all hoses, replacement of coolant plus the replacement of any unplugged or leaking parts. It is a good idea to have all hoses checked at least twice a year to see whether there are abrasions, flexibility, cracks, and leakage. And of course it is vital that whenever coolant is flushed for replacement or even during engine repairs that hoses should be replaced. Radiator hoses, expansion tanks, heater cores, and control valves are commonly replaced due to leakage or plugging. However it is important that a VW professional should be the one contacted to assess the condition of these parts since they know everything there is to know about Volkswagen components.
Volkswagen Radiator, Thermostat and Sensors
Volkswagen’s cooling system’s temperature controls include all coolant temperature sensors, radiator or expansion tank cap, thermostat, cooling fan(s) and fan clutch. These cooling parts function independently of the engine but maintain the control over the engine cooling which is made by means of sending control signals to the VW’s electronic systems.
The spring loaded valve that opens and closes based on the temperature of the coolant flowing through it is called the thermostat. You can tell that something is wrong with your thermostat when you see a high temperature reading is followed by a drop to normal temperature or a continuously low temperature—this normally indicates a sticking thermostat. Unfortunately, there are other conditions that caused these symptoms and if you are not sure what causing it then better have a VW professional mechanic to check it.
The radiator or expansion tank cap is similarly a spring loaded valve that reacts to system pressure. Its function is to maintain proper system coolant level at predetermined pressures. It should always be replaced with an exact replacement cap with the same pressure setting to obtain optimum function.
A belt-driven fan blade that pulls air through the radiator is usually included on the water pump pulley with a fan clutch to control it. The fan clutch functioned by allowing the fan to turn with the belt at low engine speed and shift to “free-wheel” at higher speeds. A damage fan clutch should not be taken for granted since it may cause your vehicle to overheat.
An electric fan that can function by itself or with an auxiliary mechanical fan is usually equipped for front-wheel-drive Volkswagen. These two types of fans are controlled via a temperature sensor that is found on the radiator specifically on the upper radiator hose or on the thermostat or water pump housing. This sensor is usually an on/off type switch with a fixed temperature setting.
The other common temperature sensors that are found on Volkswagen vehicles include: gauge sender, warning light sender, lambda and/or fuel injection sensor/s and the thermo-time switch. Controlling the engine temperature is critical to obtain high performance and emission control. But unfortunately it is also the system that is one of the most difficult to fix getting a VW professional is highly advised.
On the other hand maintenance of your cooling system sensors is a no sweat task since there is nothing to maintain in the first place, all you have to do is to keep them clean internally and externally. Likewise, checking and replacing all parts at the set factory-recommended time or mileage limit also help to maintain the good running condition of your VW car.