On board filters – air, fuel, water, lubricant – are the last lines, indeed, in many cases the only lines, of defense against fluid-borne engine problems. And, with the introduction of 2007 emissions technology, a major line of defense against environmental contamination.

Filters are items that generally don’t get their fair share of attention when advances in engine technology are being reviewed. Although the introduction of exhaust gas recirculation technology in 2002/’04 engines went fairly smoothly, high underhood temperatures generated some very unwelcome surprises. As a result, one might expect that fleets would have run into some problems with filters given their location in midst of the fluid streams.

That, however, was not the case, says Paul Bandoly, manager of technical services and customer training at Wix Filters. “As a general rule, there really weren’t issues with filtration – oil, fuel, air or coolant. The engines have continued to evolve, and as a result, the technology associated with filtration has evolved with them. The filters that are available today are designed to deal with those engines. Today’s filters have much better performance capabilities than those of just a few years ago.”

Fuel systems

Along with EGR engines came more sophisticated fuel systems. Today’s fuel filters trap and hold contaminants that are far smaller than those of earlier generations.

“Years ago, particles the size of red blood cells were not an issue,” Bandoly says, “Today, items a quarter that large have to be dealt with. Some earlier fuel systems were rather tolerant of water that might be dispersed in the fuel and carried through the system. Fuel system tolerances today preclude such a situation. Fuel/water separators have to deal with this.”

Although engineers see no looming problems with filters themselves, there will likely be some changes in maintenance schedules required as a result of the move to ultra-low sulfur diesel fuel.

“Federal regulations require that ULSD is to be available on the retail market by mid-October of this year, and there is a link between ULSD and fuel filter maintenance intervals,” says Tom Weyenberg, Lubrizol’s business manager for diesel fuel additives. “To meet diesel fuel lubricity specification, ULSD must use lubricity additives, which tend to clean out fuel storage facilities. That is, they can slowly pull out ‘water bottoms’ from fuel storage tanks and into the vehicles. The result may be shorter fuel filter life at the onset of ULSD use. Procedures need to be instituted to detect premature filter blocking as fleets switch to ULSD.”

A similar situation exists with biodiesel, which also has a tendency to clean out “water bottoms” from storage tanks and to act as a cleaning agent of fuel systems, actually, more quickly than ULSD. Donald DeRoche, manager of heavy-duty technical sales in Honeywell’s Fram group, says, “Biodiesel acts as a scrubbing agent when used in older vehicles, and it can shorten fuel filter change intervals until the contaminant gets flushed out of the system.”

Weyenberg says, “Biodiesel users may notice a shorter fuel filter life, typically for the first three months or so after switching their tanks over to biodiesel. Once enough fuel goes through the storage tank, the system will be cleaned and the filter life will go back to normal. Detergent additives can help keep insolubles dispersed in the fuel and prevent them from plugging the filter.”

Brent Birch laboratory manager at Champion Laboratories, maker of Luber-finer filters, says, “Users need to be ready to change fuel filters more frequently than in the past to achieve peak performance. This is especially true during periods of high demand because in these periods fuel quality often suffers. The solvent action of biodiesel blended fuel can cause short fuel and dispensing filter life as varnishes, gums, sediments and fuel degradation products are cut free. Due to varied fuel quality and content, and the fact that fuel used for cooling engine ECMs and/or fuel returned to the tank, onboard fuel is subject to degradation from heat aging. We recommend changing fuel filters at each oil filter service interval, as a minimum. When switching to a fuel with a lower sulfur level, it is recommended to change fuel filters at that time. The lower sulfur level fuel has fewer aromatics and the aged sealing gaskets on used filters may not be resilient enough to compensate for any shrinkage, allowing leakage.

“Injection systems are becoming much more sophisticated with each new emission tier,” he says. “System pressures will continue to rise in pursuit of the ‘perfect burn’ as new emission standards are mandated. As pressures increase, the system tolerance for particulate contaminant decreases, therefore fuel filter performance must also be taken to a new level of protection. Fuel filters cannot be expected to last indefinitely, and when they plug or clog and the equipment goes down too often the filters are blamed. Users need to understand they need to select a fuel filter of quality design and manufacture to trap the abrasive particles that cause fuel injection system wear.”

Cooling systems

With all the conversation about high underhood temperatures of trucks equipped with 2002/’04 EGR systems, it would seem that problems with cooling systems would have been encountered. That, however, doesn’t seem to be the case. For the most part, cooling system components in these trucks also performed adequately.

Many of the problems encountered were the result of an inability to dissipate all the heat that was generated. It simply didn’t happen fast enough, and that can cause problems.

“Problems encountered with EGR engines have been caused by the lack of coolant filters,” says George Sturmon, CEO of Atro Engineered Systems. “Some coolant suppliers have recommended not using them which, in my opinion, is irresponsible. The use of glycol, which has operating temp max of 245 to 260 degrees F, ensures glyoxylate formation particularly when EGR coolers run much higher than that. Many other additive packages do not stand up well at these temperatures for extended periods, so formations plate out on the cooling surfaces. Many of these are lumped together and explained under the heading ‘scale.’ When these formations break off in small chunks, a lot of maintenance issues can and do occur. There seems to be a return to coolant filters, but the micron rating is not mentioned. With underhood temperatures exceeding the coolant temperatures, it seems likely that coolant damage by heat could be accelerated.”

Dean Swick, OEM sales and account manager at the Penray Cos. says of the 2002/’04 EGR engines, “We found that the additive package and the ethylene glycol both held up to the high temperatures generated by the EGR technology. We didn’t see any problems. We didn’t see any additive depletion outside the normal amount you’d see in any heavy-duty cooling system.”

Even with the excessive underhood temperatures with 2002/’04 EGR engines, the maintenance procedures used earlier generally worked well with these new engines. Swick says, “The maintenance intervals technicians relied upon prior to the introduction of EGR engines held true for engines introduced after EGR. The maintenance intervals could remain the same, and you could adequately protect your cooling system.”

With regard to 2007 engine technology, Swick says, “We have numerous trucks under tests in conjunction with OEMs and have been monitoring coolant technology – standard conventional coolant, extended life coolants and hybrid coolants that are slowly making their way into the marketplace. These are tests on trucks running in real world conditions, on both over-the-road and city routes. We’ve found that our technologies have held up to the requirements of the 2007 engines. We haven’t seen anything that concerns us regarding the stability or efficacy of the technologies under conditions seen the new 2007 engines.”

Problems are not likely to be the result of ineffective components. They are far more likely to be the result of using incorrect maintenance procedures for the coolant in the truck’s cooling system. According to Baldwin Filters, poor cooling system maintenance causes an estimated 40 percent of all premature engine failures. Coolant filters protect your engine by trapping contaminants and distributing supplemental coolant additives (SCAs) into your cooling system.

Up until recently, maintenance practices have been rather limited because product options have been limited. That, however, is changing as extended life coolants along with other coolant technologies are making their way into the trucking industry.

“There’s a greater selection of coolants than we saw 10 or 15 years ago,” Swick says. Technicians are going to have to identify the coolant in order to maintain cooling systems properly because different technologies require different maintenance procedures. New filters are currently being developed that will give fleet technicians more options with regard to coolant maintenance. Within the next six months, we will be offering fleets new cooling system maintenance products and procedures that can coincide with the maintenance procedures they perform on other systems.”

The correct choice of cooling system filters depends on the type of coolant installed in trucks.

“Cooling system technology has been driven by the combination of higher engine temperatures and the need to decrease maintenance costs,” Bandoly says. “Now we have low silicate antifreeze, organic acid antifreeze technologies, hybrid organic acids and organic acid-based products. For many years, people have been accustomed to buying different types of lubricants for different applications, but until recently they’ve had a single type of coolant. That’s changed, and different coolant types require different maintenance procedures.

“Some suppliers are saying that all these different kinds of coolant are compatible with one another. In the laboratory that might be true, but how should a system with a combination of coolants be maintained? Part of that question must be what kind of filter needs to be used. All reputable coolants are fine, but they shouldn’t be mixed in any one truck.”

Technicians need to properly identify the coolant being used in a cooling system and how to correctly maintain it. Topping off with unknown chemistry may cause problems.

“Understand the coolant you have, and understand its maintenance needs,” Bandoly says. Not paying attention to cooling systems is not acceptable. Even ELCs with their extended maintenance intervals need to be maintained. You need to actively maintain your cooling systems regardless of the technology used.

Lube filters

As far as engine oil filters are concerned, the transition to EGR technology was made relatively seamlessly. The trucking industry is a very demanding market so component suppliers undertook extensive field-testing programs to ensure their products performed adequately in the 2002/’04 engines.

“Elastomer durability is usually in question as oil temperatures increase,” says Luber-finer’s Birch. “The same holds true for the filter media and adhesives. During development work for 2002/’04 engines, many heavy-duty lube oil filters increased in physical size to handle higher oil flow rates for the new generation of engines. A lot of development work went into the design and qualification of these filters, including exhaustive vibrational analysis due to their considerable mass when full of oil. Elastomer performance was enhanced to handle the increased operating temperatures and acid generation of the emission engines. Contaminant-holding capacity was increased during this period. Due to the physical size and mass of the oil filters, education and training of technicians regarding the importance of proper filter tightening torque became an important issue.”

For 2007, conditions will be even more difficult than those experienced in 2002/’04 engines.

“A given with heavy-duty oil filters is the need for a construction that will offer a large safety factor regarding time in service, exposure to the elements, filtration performance and general durability,” Birch says. “The optimum filter design should have reserve capacity ‘headroom’ to run the drain intervals the engine manufacturer specifies, and/or responsible drain intervals the user has oil analysis data to support. Particle removal efficiency is always an important aspect to control engine wear and should be balanced with the required dirt-holding capacity. By-pass filtration, is still a viable option to reduce engine wear.”

Keith Bechtum, liquid filtration product specialist at The Donaldson Co., says that his company is not anticipating any new filter maintenance procedures for lube filters, but that the company is evaluating the introduction of SAE CJ4 oils and potential changes to its product line in the future to maximize effectiveness.

Air filtration

Tom Miller, director, product management–air filtration for The Donaldson Co., says that there really are not significant issues with air filters related to EGR engines with the possible exception of perhaps the need for higher air flow. However, he states that it is not significant enough to affect Donaldson’s product development.

“While 2007 EGR engines run hotter and at higher temperature, our filters and housing have to be built to withstand higher temperature,” says Miller. “We have developed the Donaldson PowerCore specifically for these engines.

“Air filter service for 2007 engines will be basically the same. Some models may have side access due to the limited underhood space.”

It appears that you will be able to rely on tomorrow’s filters as you have on today’s, but make sure your shop personnel understand the procedures for their proper maintenance.