Optimizing oil drain intervals

Many manufacturers of heavy equipment have changed their recommended oil drain service intervals from 250 to 500 hours in recent years. But the correct service intervals for your off-road equipment can change drastically depending on dozens of different variables.

To prevent contractors from performing oil changes too early or too late, equipment OEMs and lube suppliers have begun talking about “optimizing” drain intervals. And while “optimization” might sound like something from a sales pitch, when it’s applied to heavy equipment service intervals it is a real, scientifically derived number that is vital to the successful management of your fleet.

What is optimum?
“We started using that word as opposed to drain extension because with optimization you are customizing the drain interval to a specific fleet’s operating condition and make and model of equipment,” says Mark Betner, heavy-duty product manager for Citgo. “You don’t automatically assume drain extension is the goal. Some people may be in a situation where they may be overextending their drain interval and actually hurting their equipment not knowing what’s going on with their oil.”

Charlie Yates, director of field engineering, BP Lubricants America, notes that any consideration of optimum must also take into account your company’s primary business and culture. Are you in a quarry running machines 24/7 or paving roads and only putting 1,000 hours a year on your main machines? Is your maintenance centralized or decentralized? Do you work in one geographic location or spread out over several states?

“The other question you have to ask is about the discipline of your maintenance,” Yates says. “Do you have a competent maintenance department with computerized record keeping and tracking? If those aren’t happening it’s very difficult to get your arms around the right thing to do.”

Oil drains are often tied to other service intervals, cautions Brian Schmidt, manager of commercial and industrial off highway construction and mining for ChevronTexaco.

“In the real world you have to consider the additional maintenance you perform when you bring that machine in for an oil change. The oil change may be a trigger for service intervals on hydraulic and cooling systems, transmissions and final drives. The service intervals for these other fluids are influenced by the oil drain interval. So if you want to extend your oil drain you have to consider the big picture.”

Planning and partnering with your vendors is a key component of any oil drain optimization plan.

Defining your motivation
On the surface it may look like oil drain extensions do save money. If changing the oil on a large dozer costs $600 in labor, oil and filters, cutting back from five to three oil changes a year over a four-year period adds some money back into the budget and makes you look like a hero. But cash is not always king, especially for contractors who put a premium on uptime.

“Don’t get hung up on the cost savings of just the lubricant alone because that’s often a very small factor when we start relating it to productivity and increased availability if you’re maximizing uptime,” Schmidt says. “The cost of the fluid and the labor costs of the mechanic are often not the driver in making the decision, especially if that equipment is fully utilized.”

Another reason you may want to establish a rigorous oil drain optimization program is to compare your maintenance costs across models and brands, Schmidt says. “We have found from experience it helps owners determine what pieces of equipment are running most efficiently and that can determine their decisions on what types of equipment they buy the following year.”

Understanding the variables
While 500-hour service intervals may be the norm for most equipment today, there may be times when you can double that and times when you have to cut it in half. One of the best indicators of how hard an engine is working (and how fast the lube oil chemistry may be consumed) is the fuel burn rate.

“We’ve seen into situations where we’ve looked at the fuel burn rate and found that 250 hours is an extended drain for machines with heavy loading that are burning the maximum,” Yates says. “You should understand the effect in hours to overhaul and attendent cost you will realize for that maximum fuel burn.”

And keep in mind fuel burn rates change quickly – for instance, when your excavator goes from digging soft, loamy soil to heavy, sticky clay or your haul trucks go from a flat site to one with steep grades. Operators who tend to gun the engine likewise burn through a lot more fuel than those who finesse the machine.

And airborne dust is the one contaminant that can sink an oil drain extension program faster than any. “More often than not in off-highway machines the air filter becomes the weak link because if you get dirt in the oil it doesn’t matter how good the oil or the lube filter is,” Betner says. “Airborne dirt is probably the No. 1 killer of engines in terms of catastrophic failure. It literally scrapes the engine to pieces.” The problem can be held in check if the air filter is changed frequently, but if your oil drains happen only every 500 or more hours, it may fall to the operator or a technician in the field to check and replace the air filters.

The reports you get from oil analysis labs provide insights into your equipment’s health and help you time and predict future maintenance needs.

Oil analysis and trending
A thorough oil analysis program is essential to optimizing your drain intervals. Without the information you get from the analysis you have no way of knowing the condition of your oil – whether it can go another 100 hours or whether you’re damaging your engine by leaving the oil in too long.

“If an organization is not on an oil analysis program it goes without saying it cannot optimize drains,” Yates says.

Oil analysis provides a maintenance report card, Betner says. “The three major systems your engine depends on for survival are the air induction, cooling and fueling systems. If any of those create contamination, it can destroy the ability of the oil to protect your engine.” Frequent oil analysis will show you where the critical thresholds are, enabling you to change the oil no earlier or later than necessary.

“You can get your arms around all this through oil analysis,” Betner says. “If analysis shows you have a high frequency of occurrence of any of these things, you’re not a good candidate for a drain extension. You have to get the contamination cleared up first.”

Trending compares multiple oil sample results over time. Plot these points on a chart and you can see where the condition of your oil is heading. When you start a pilot program to determine optimum drain intervals on your equipment these charts will show you when you’ll likely need to change oil. But you need to sample at regular intervals between oil changes. “Take it in short increments,” Yates says. “What you want is to have your sampling at the midpoint between oil changes, or more frequently as needed before changing. You don’t want to lose that inspection period.” The exact frequency of these samples should be worked out in discussions with your engine and lube suppliers.

Most lube suppliers and independent oil analysis labs now support their programs with e-mail and Internet-based reporting options. “Today’s computerized oil analysis programs make it a lot easier,” Betner says. With them you can create spreadsheets on your whole fleet and view trends as opposed to trying to figure out the data by reading through a stack of individual paper reports.

“Be sure whatever oil analysis program you use,” says Yates, “it can give you the information on a macro scale, so you can look at your whole fleet. If you have a small fleet you can probably do it on paper, but as your fleet starts to grow it becomes a monumental task and you’ll need to computerize your oil analysis and maintenance records.”

Filters, coolants and other systems
The decision to optimize or extend drain intervals also changes how you maintain the other systems around your engine. Just because your oil can go 500 or 600 hours doesn’t mean your oil filter can.

“I like to start at the front of the machine and make sure the coolant, engine oil, transmission, hydraulic system and final drives all have the right product in them, says Schmidt. “It’s important to have a high quality lube filter, but also consider your air filters, fuel filters, transmission and hydraulic filters.”

Then add up the costs. “You have to ask yourself if it’s really worth extending the oil drain interval,” Schmidt says. “There is a perception that doubling the oil drain brings cost savings, when in fact it may not.”

Lubrication oils have gotten increasingly better in recent years – so good in fact that it’s primarily the quality of the oils, more than what they’re doing with the engines, that has allowed manufacturers to extend recommended oil drain intervals out to 500 hours. And extended-life coolants, long popular with on-highway trucks, are starting to make a dent in the off-highway market as well.

“Coolants are important,” Schmidt says. “A significant number of all engine failures are related to the cooling system in some manner. Most often we find a drastic chemical imbalance in the coolant because the system was not maintained. People tend to overlook this, which is why extended life coolants should be considered whenever you’re extending oil drain intervals.”

Partnering with suppliers
Betner says it’s important to be proactive with all your suppliers. “Tell them what you want to do and ask them for their advice and support. People are always concerned about warranties and you want to show that you are responsibly making decisions based on information that supports those decisions. Rarely will you have a problem with a dealer or an equipment manufacturer as long as you have the data and can support what you’re doing.”

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