Auto Service World
Feature   July 1, 2007   by John G. Smith

Cooling Cash

Cooling systems are lasting longer than ever, but they still present maintenance opportunities

With the pressures of higher under-hood heats, more of the stop-and-go traffic that will put any fan clutch through its paces, and the ever-present push to make lighter components, it’s surprising that today’s cooling systems don’t require more time in the shop.

But today’s system designs and enhanced fluids have little in common with those of the past.

Overflow reservoirs that emerged in the 1970s keep pressurized systems completely filled with the all-important coolants that transfer heat, prevent deposits and lubricate the water pump. Long-life coolant formulas maintain their properties for as long as five years, compared to the required bi-annual flush-and-fills of the past. Fan clutches include bigger bearings, while improved hose compounds slow the process of electrochemical degradation. Heck, the radiators themselves are more effectively shielded from road debris.

As trouble-free as these systems can be, however, they still require regular maintenance … and a strict attention to detail.

Something as simple as the top up of a long-life coolant can lead to significant problems if technicians reach for a traditional green formula that prevents corrosion with silicates, phosphates and nitrates.

“If you have an extended life coolant already in the reservoir, and you top with a silicate base form, it will all go to the lowest common denominator,” explains Megan Currie of Honeywell Consumer Products, which sells Prestone branded offerings. The life of a five-year coolant will suddenly revert to two years and 60,000 km, and the mixture of different inhibitors will form calcium that can stick in seals and lead to leaking water pumps.

In heavy-duty cooling systems, the altered formula can even lead to liner pitting.

“It changes the balance of the formula, so you’re best to go with an extended-life coolant with a top-off,” she says of the mixtures.

Even the colour of the coolant indicates a difference that should be noted.

Fords, for example, require the yellow Hybrid Organic Acid Technology (HOAT), while GMs use an orange Organic Acid Technology (OAT). Think there is no difference? Ford has gone so far as to stick “no orange” labels on its expansion bottles, because the HOAT is specifically designed to limit cavitation-related corrosion. (Prestone answered that need with a fluid that can be mixed with any of the nameplate-specific formulas.)

Water from the garage tap should also be avoided when mixing the requisite 50/50 solution, since the salt in softened tap water can lead to electrolytic corrosion. That may promote pre-mixed solutions as an effective option for minor top-ups.

But the wrong choice of coolant, Valvoline notes in its literature, can corrode metal and deteriorate gaskets.

“There is a difference in the formulas,” agrees Bob Rose, national sales manager of Fenwick Automotive, noting how lesser-quality glycol offerings can eat away at impellers and the aluminum housings around hose connections. And once it’s pitted, chewed or deteriorated, the water pump’s housing can’t be reclaimed for the rebuilding process.

To compound matters, it takes longer than ever to replace a water pump. When they were easily accessed, they could be swapped in less than 2 1/2 hours, but today’s replacements take twice as long.

Inspection procedures should also take note of the condition of the fan clutch.

“The fan clutch is a big thing — it can be leaking and cutting in and out at the wrong time,” Rose observes. “It can cause a complete water pump failure by damaging the bearing … by the time you start to hear noise, it’s too late already. It can cause a catastrophic failure if the bearing comes out of the housing, or the bearing shaft snaps and goes into the rad.”

If it’s difficult to turn the fan, the fan clutch may have locked up, spinning at the same speed as the water pump. If there’s no resistance at all, the fan clutch may not be engaging at all.

Metal fan blades should also be checked for signs of cracks near the mounting position, caused by the natural flexing of the fan blades that are designed to flatten out as they spin and rotate, Rose says.

“Some of them have plastic fans and it’s not an issue,” he says.

Signs of minor leaks, meanwhile, can be addressed with a Stop Leak as a temporary solution for cash-strapped customers.

“The cost of a repair is astronomical,” says Richard Navin, sales manager of the Radiator Specialty Company of Canada. “If the customer [balks] because of the cost, they would recommend the Stop Leak.”

The first step when using such a product, however, is to flush the cooling system to remove any scale, he notes.

“If the system is at the age where it has a leak, it’s very likely to have corrosion and dirt and scale in the system that’s already half-clogging some of the passages in the radiator — or particularly in the heater core [passages] that are even finer,” Navin explains, referring to the importance of promoting the service. “There are always impurities getting into the system. Either it’s through leaking gaskets, or oxidation.

“It would be a very valid thing for an installer with a regular, loyal customer base to recommend [flushing the system] at an interval of three years.”

The added benefit of the flushing procedure is that it will help technicians spot the presence of oil, which can indicate a more serious problem. Of course, the coolant needs to be delivered to be effective, so technicians should also pay particular attention to the condition of hoses.

“In general, one thing that can get overlooked is the potential of the hose sale or the potential of the hose replacement job,” says Marc Therrien, Engineered Products, Goodyear Canada. “Electrochemical degradation, that is still what we call the ‘invisible enemy’… physically, sometimes you don’t see anything. The hose still looks good on the outside.”

It’s why it’s important to replace lower radiator hoses, heater hoses and bypass hoses on the basis of time they’ve been in service.

Still, there are some signs that can be spotted, he explains. By squeezing a hose near its end, a technician may be able to identify softness associated with the so-called invisible enemy. A differential in pressure that’s caused by degraded material can also lead to visible bulges. And heater or low-pressure rad hoses can turn brittle with age.

During installations, technicians need to be careful to avoid the kinks that can restrict the flow of the coolant or place added pressure on the reinforcement fabric that lines the hose, he adds. Goodyear recently introduced the E-Z Coil heater hose with a stiff wire spine that can be bent into any shape, to avoid such a problem.

They’re the types of steps that can make long-life cooling system designs last even longer, and lead to some cool cash from satisfied customers.


Fenwick Automotive Products

Goodyear Canada Inc.

Honeywell Consumer Products

Radiator Specialty Co. of Canada

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