Are you seeing water pump comebacks?

MACS (August 2013): The water pump is the heart of the cooling system and today’s pumps are made better than ever, with such features as stainless steel impellers and more durable seals. But although they seem to be lasting longer, they aren’t matching the durability of cars in general.

An apparent reason is contaminated coolant, according to a report by Gates, a major aftermarket supplier of belts, pumps and other aftermarket cooling system parts. Gates found that 95% of the water pump warranty claims it received were from cars that had not had the cooling system flushed. This doesn’t mean that cooling systems need to be flushed to avoid a pump failure. It means when a replacement pump has failed during the warranty period, in 95% of the cases the cooling system had not been flushed when the new pump was installed. What’s more, Gates says a contributing factor in most of those failures was contaminated coolant.

What is contaminated coolant? Today’s cars and trucks have more heat exchangers than before, for the transmission, turbo, engine oil and sometimes EGR coolers. If the soldering flux left over from manufacturing was not totally cleaned out before the heat exchanger was installed, it can lead to corrosion. This is also true of replacement heat exchangers, suggesting it’s a good idea to flush a new radiator before installation.

Another definition of contaminated coolant is one that has never been changed. Many car owners assume the typical five-year/100,000 or 5/150,000-mile interval means “never.” Even if the coolant does get changed, the system may still not be properly flushed. Draining the radiator only removes 30-35% of the old coolant. And finally, if the cooling system is ‘topped-up’ with tap water, that’s almost sure to introduce minerals that will react with metals in the cooling system.

To minimise the chance of a come-back after installing a new water pump, flush the cooling system and refill it with the factory-recommended coolant.

Article sourced from MACS Worldwide B2B automotive aftermarket blog – available only to VASA members and MACS subscribers.