Keep It Cool

Today’s machinery is built to work hard in the scorching summer heat, but inspecting and maintaining cooling systems is critical to avoiding costly equipment failures and losing time on the job.

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One of the best practices for maintaining equipment like skid-steers, mini-excavators and other machines used by onsite system installers is inspection of the cooling system prior to and during machine use. This practice might just make the difference between a long, productive machine life and an expensive, premature death.

Inspecting and maintaining cooling systems is a relatively easy thing to do, yet many service shops thrive thanks to contractors who don’t bother with such simple practices. This practice is especially important when temperatures soar. Machines can overheat as the ambient temperature rises. The potential for overheating can also be related to the type of work being performed.

According to Gregg Zupancic, marketing product manager for John Deere skid-steers, “Frequently, a small, compact machine with a bucket is not likely to overheat as they’re designed for that workload. What causes them to overheat more often is the type of attachments that get plugged into the hydraulic system.”

The biggest Deere machine, says Zupancic, is on a 333D track loader. “If a guy is running a high-capacity hydraulic attachment like a mulcher full out, that machine is designed to run efficiently at a high ambient temperature, but if the coolers are not kept clean, an audible alarm will let the operator know if the machine ever gets close to red line. After that, there is a built-in machine protection system that will automatically shut the machine down if the operator keeps going.”

Hydraulic attachments like trenchers or tree grinders require a lot of hydraulic capacity and flow. Extreme ambient temperatures could result in overheating.

Inspect for dirt and debris

“One of the ways these machines overheat most often is when cooling radiators get clogged with dirt and debris,” explains Steve Perkins, service tech for Bingham Equipment, which operates 11 dealerships in Arizona. “In some areas of the country, like ours, powder-like dirt kicks up a lot of fine dust that gets into these radiators. That’s the fastest way to create an overheating problem.”

“I’ve seen radiators that actually exploded – where the tank just blows off the machine,” Perkins notes. “Some systems have dual fans, and if one stops, uneven heating takes place that can blow the tank.” Often, you can hear if one fan has dropped off, he says. Thus, a good walk-around inspection includes listening to a machine as well as visual examination.

But if the machine is kicking up a lot of dirt, dust or sawdust from grinding wood, the fans will pull that debris through the radiator and clog it relatively quickly. Trained techs recommend blowing the coolers clean with air every day. Under the same conditions when operating in 100-plus degree temperatures, this may need to be done on hourly basis.

Hydraulic oil can damage hoses

Perkins also suggests coolant hoses and belts be routinely inspected for cracking and other signs of deterioration. His biggest concern, however, lies with hydraulic oil spills. “Hydraulic oil can soften and weaken hoses,” he warns. “Any hydraulic fluid that gets on hoses and belts should be wiped clean right way. A leaking or burst hose doesn’t happen right away, but it can certainly lead to that problem over time.”

Make sure coolant is fresh

Steve Overdeck, vice president of sales and operation for Kost USA, says 40 to 60 percent of engine failures are coolant-related. “What that means is maintenance technicians are using an improper coolant or topping off with the wrong coolant,” he says. “It can also happen if they’re not using proper maintenance.”

Bobcat recommends coolant changes every 1,000 hours or every two years. According to Perkins, all Bingham Equipment locations follow this service interval. Flushing is also done only when the fluid looks questionable.

Mixing two or more types of coolants in equipment is a no-no. Bobcats, like many other compact machines, use propylene glycol vs. ethylene glycol coolants. Mixing the two will result in coolant “gelling” – which spells certain death for the radiator and risk to the entire engine. 

Ethylene glycol is always green in color. Propylene coolant can be different colors. Bobcat’s propylene coolant is a unique purple color while their hydraulic fluid is orange. This helps keep technicians from mixing the wrong fluids.

You should also decide whether to use an extended-life coolant or the type that is mixed with distilled water. Once you choose which coolant to use, stick with it and never combine the two.

You can purchase test strips from a local dealer to check your cooling system’s protection levels. A hydrometer is another tool to measure your cooling system’s specific gravity level and delivered degrees of protection. The degree of freeze protection – how much the temperature can drop below the freezing point before causing an adverse effect on the liquid in the system – is related to the density of the antifreeze.

Keep coolant levels up

If coolant is low, many technicians will “top off” the system with either water or more coolant mix. Adding hard water (not distilled) can result in radiator hot spots while lowering the temperature rating of the system. More often than not, topping off is when incorrect coolants get mixed. The best practice is to change coolant per manufacturer recommendations, keep a record of coolant changes and types, and when low, inspect the system to find out why. There’s probably a leak somewhere.

Overheating can also cause coolant to gel. Once coolant gels, it will likely result in a blown engine. The radiator will be shot, too. Repair costs to your hardworking equipment may now range from $5,000 to $10,000 for a new engine and radiator.

Radiator cap gaskets can age and deteriorate. According to Perkins, when the psi drops too much, the machine will heat up a lot faster. The cap should be tested to be within the manufacturer’s psi rating. Making sure pump belts are in good shape and have proper tension is another good step in inspecting the cooling system.

Be especially careful with diesel engines

Proper cooling system maintenance is especially important in diesel applications. Overcooling, pitting, overheating, cracked heads, cavitations, piston seizures and plugged radiators are some common cooling system failures. It is important to maintain the recommended SCA (supplemental coolant additive)/DCA (dry coolant additive) levels in your engine’s cooling system and maintain the manufacturer’s specs.



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