Auto Service World
Feature   August 1, 2004   by Auto Service World

Water pump market a dirty business


If it weren’t for poor maintenance practices, the water pump market might only be a fraction of what it is.

And, in a roundabout sort of way, it might be long-life coolants that have helped keep water pumps as popular an item as they are.

“We seem to sell more all the time,” says Richie York, York Auto Supply, Moosejaw, Sask. “It isn’t bad, but it is like everything else in that you have to stock so many more numbers than you used to need to cover the market.

“But,” he adds, “the sales numbers have stayed pretty constant over the past number of years. I would have thought it would drop off, but it hasn’t.”

Perhaps at least part of the reason is the increased demand put on the water pump. Hotter conditions under the hood tax the entire engine cooling system more than in days of yore, but changing construction–more aluminium usage, for one–is only part of the story, and a less critical one than the “maintenance-free” myth that has gained traction in this market as well as other underhood systems.

“The biggest failure we’re seeing is simply that the cooling system is not maintained,” says Craig Gottfried, tech line supervisor, Master Parts Div. Contamination is, he says, the greatest culprit in early water pump failure and, often, it is the seal which pays the price. When the seal goes, the pump starts to leak–and few things will get the customer back to the service bay quicker than a puddle of liquid under the car.

And, while it is the water pump that takes the blame, it is often hard to determine just what the cause of the problem was. There are even ongoing efforts to blame Dex-Cool type coolant and General Motors for myriad problems with cooling systems, including water pump failures.

“But there is nothing that we can come to a conclusion on,” says Jeff Sandt, vice-president sales and marketing, ASC Industries. While he says that their engineers do see similar failures within applications with “a certain coolant,” indications are that this has more to do with consumers mixing chemistry than problems with one coolant chemistry or another.

“There is a lack of understanding of what they have and they are topping off systems with other coolants.” Since they weren’t meant to be mixed, the fallout can be unpredictable, but it can’t be good.

“When the chemistry of the system changes, you head down the road to corrosion. All antifreeze has an inhibitor package in it, and when you top off with the wrong antifreeze or water with a lot of calcium, then we see the internal failure of the water pump.

“But,” he emphasizes, “the direct correlation between orange coolant and failures is not being seen.”

More to the point, he says, the increasing use of dissimilar metals means that the entire cooling system can very easily become prone to generating an electrical current that accelerates corrosion and erosion of metal.

“When you have an aluminum block or an aluminum water pump, you can get electrolysis in the system. That is another piece that contributes to premature water pump failure, especially if the coolant liquid creates an acidic environment. You can have an electrical charge running through the system and that will attack softer metals.”

Gottfried says that one particular “problem application,” Dodge full-size trucks with V8 and 3.9L engines, have seen pump body failures that seem to point to electrolytic erosion.

“I have seen more calls from this than probably we ought to. I guess most of the cases are in applications where the truck is a people hauler or a service truck with a boom,” says Gottfried. “It seems more prevalent in those applications, but extra ground wires seem to take care of it.”

Of course, not all factors affecting the life of a water pump are internal. Pumps are, after all, driven by belts that can transmit shock and vibration.

“We are seeing a lot more bearing failures than we should see. The only thing there is the tensioner.” He says that while the prevailing view is that a tensioner spring will relax over time, he believes that it also loses its ability to dampen the shock loading on the water pump’s pulley and bearing.

“Most of the time, the length of service you will get out of the system will increase when you replace the tensioner.”

Perhaps this was the problem on a water pump-eating Oldsmobile that a York Auto Supply customer owned.

“I had an horrific experience with a guy who was changing water pumps more often than oil changes,” says York. “It just kept leaking. He could get 3,500 km before it would start to leak.” The car owner, a retired technician, got so concerned he started travelling with a spare in the trunk.

Eventually the problem resolved itself, without a firm conclusion as to the cause, but it gives pause for thought to stop thinking of the water pump in isolation.

“There is a lot of stuff happening under the hood, especially with the automatic tensioners. It is imperative that the technicians and the jobber people take the time when they have a problem to make sure that the tensioners and the idlers are okay,” says York.

“Even as we see electric pumps coming on,” says Gottfried–the company is already supplying some applications to customers in Europe–“the reality of the cooling system is going to remain the same.

“My suggestion is to keep [the cooling system] clean and happy,” he offers with a chuckle.

Air Contamination

According to Jeff Sandt at ASC Industries, problems can arise when attempts are made to top up hot cooling systems.

“If I take my vehicle into a quick lube and the cooling system is warm, they are going to look to top off the fluids. In the Ford Contour, if you trap air in the system, you can’t evacuate the system unless you put it on a vacuum.

“You suck the cold air in, it gets trapped in the system and you end up with an air pocket between the seal faces.”

This causes the seals to overheat, which ends up in an early failure for the seal and a water pump replacement.

Comeback Prevention

– Always ensure that the cooling system is flushed and a fresh coolant mixture is used with any water pump replacement. Contaminants can dramatically shorten the life of a water pump.

– Use the proper coolant. They are not all the same. And do not reuse old coolant, as it could contain the contaminants that ruined the water pump in the first place.

– Sealants, such as RTV, should be used carefully. Excess sealant can end up causing damage in the cooling system.

– Check the belt, tensioner, and pulley. Each should be checked for condition and function, especially tensioners. Too much tension, or too much shock being transmitted to the pump pulley, can cause premature bearing failure.


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