Cleaning the cooling system when replacing the water pump has recently become a hot topic. The garages do – of course – wonder why this extra workflow suddenly is necessary when it has never before been required? Some car owners will probably also be puzzled by the extra posting on the garage bill, and the garages should therefore be able to provide them with a well-based answer. The explanation is not quite simple, but let us start with the reason why it is necessary: the water pump.
Over the recent years, the design of many water pumps has been characterized by downsizing. In some cases, it has been necessary because the space has become too tight due to a downsizing of the engine size. In other cases, however, it is difficult to understand the reason for using a smaller water pump. Downsizing of the water pump has also led to a reduction of the dimensions of the shaft, bearing, impeller and not least the seal ring. Simultaneously, it has been necessary to increase the pumping speed to achieve the same performance as before – i.e. to pump the required number of liters of coolant around the system per minute. As a rule of thumb, a pump must circulate the cooling system’s content 20 times per minute. In a car with a 5-liter coolant, the pump must therefore circulate up to 100 liters / min. However, in many cases, the water pump also compensates for the downsizing of the engine size, resulting in a reduced area on the surface of the engine, which is used to transfer heat to the coolant. Add to this a higher performance, which applies to many diesel engines causing the increased heat generation, it is not difficult to imagine how hard „the life“ as a water pump is. And once again, it is only possible to compensate by increasing the rotation speed. The increased speed, combined with the smaller bearing and packing ring, has made the water pump a more exposed part of the cooling system, which compared to previously is more vulnerable to impurities in the coolant.
The most common error source of impurities in the cooling system is the coolant. Incorrect mixing ratio and the use of common rather than demineralized water is not uncommon among car owners who – in connection with a leak in the cooling system – try to fix the error themselves before the next garage visit. The use of plain water leads to calcification of the cooling system and lime scale is comparable with abrasive in a cooling system, which is certainly not something the water pump gasket likes. But the cooling system components – the cooler, the heater, the engine, the hoses etc. – also pollute the cooling system with deposits over time. This means that by the time of a car’s life cycle, where it typically finds its way to a garage on the free aftermarket, the cooling system is often very polluted – and a cleaning is required if the problems should be avoided.
A prerequisite for performing a thorough cleaning of the cooling system is to use both flushing tool and cleaning fluid. There are different flushing tools in different price ranges, and there are several alternatives in terms of cleaning fluids. At Triscan, we do not offer the cleaning fluid, however we do offer two alternatives within flushing tools: Gates Power Flush (no. 8601 91002) and JWL (no. 8601 91001). Please also see our video, which shows the difference between cleaning the cooling system without and with Gates Power Flush flushing tool.