No Room for Cheating On EGR Engine Care

Sept. 28, 2010

October is here and the sky hasn't fallen, even though diesels with exhaust-gas recirculation (EGR) are now coming off assembly lines. EGR adds complexity and cost to a new truck, but engine builders have established no maintenance requirements for the special apparatus. Their advice: Pay close attention to oil changes and the cooling system maintenance.

EGR sends varying amounts of cooled exhaust gas back to the cylinders to displace oxygen, which lowers combustion temperatures and reduces smog-forming NOx. EGR gear includes special valves, a water-to-gas cooler, and in some cases a variable-geometry turbocharger.

A few of the most recent diesels were designed with EGR in mind. But older models needed redesigned pistons and new fire rings to contain soot and acids that can seep into crankcases. What gets through will be dealt with by new CI-4 motor oil formulated especially for EGR'd diesels.

Engine makers say EGR components will last indefinitely. None has scheduled any special maintenance, and all note that the systems are monitored by the engines' electronic control modules. Drivers will be alerted via warning lights to any malfunctions; these will also be logged in the ECMs' memories as fault codes.

Cummins says the same types of valves, coolers and VG turbos have been running in Europe for several years, albeit in smaller light-duty diesels. Parts in its commercial truck diesels are extra stout, with EGR valves lubed for life and the coolers made of stainless steel, says Tom Kieffer, executive director for marketing.

Coolers have large passages, ½ inch wide by ¼ inch tall, so exhaust particles will not stick and create hot spots. Engine coolant passes through the cooler, carrying away heat from the recirculated exhaust gasses. Truck builders have enlarged radiators and enhanced the flow of air under the hood so this extra heat can be shrugged off.

Highway tractors with EGR'd Cummins diesels have accumulated more than 6.4 million miles, Kieffer says. The highest mileage achieved by any one engine is now over 200,000, which is not high by over-the-road standards.

Volvo has 24 test vehicles running with its V-Pulse system, says Jim Fancher, marketing manager for power trains. Three are in vocational trucks. V-Pulse consists of two poppet-type valves, a reed-type anti-backflow valve and a water-to-gas cooler; they need no special maintenance.

The cooler features a turbulator that spins the coolant and gases to agitate them so any contaminants remain suspended; thus the cooler is self-cleaning, Fancher says. V-Pulse uses a standard turbocharger instead of the more complex variable geometry type.

Detroit Diesel in the last two years has built 2,500 EGR'd diesels for city transit buses throughout North America. These are 8.5-liter Series 50s, which are essentially four-cylinder versions of the six-cylinder, 12.7-liter Series 60. Transit bus experience may be a good indicator of how cooled EGR will work for owners of construction trucks, which, like buses, stop, start and idle a lot (see caption above).

Series 60s have the same type of EGR system. Along with internal redesigns, engineers also cut about 25 pounds out of the S60. That's about what the EGR gear weighs, so the S60 remains the lightest big-bore diesel available, says Chuck Blake, a staff applications engineer.

Keep things clean

Although EGR parts themselves should need little or no attention, basic maintenance becomes more important. "Before, we would lay out the schedules and say, you should do maintenance,'" says Fancher at Volvo. "Now, you must do the maintenance. Before it might have been okay to cheat a little on oil changes, but now it's not."

Mark Wildman, manager of field service for International Engine, agrees. "The big thing is maintenance—clean air, clean fuel and clean oil," he says. Oil and filter changes must be done on schedule, and only good, properly managed fuel delivered to the engine. If you do not now use a fuel filter/water separator, you should be sure it's included on any new chassis you buy. Air filters should be changed on schedule, or as indicated by a monitoring gauge.

Oil change intervals must not go beyond recommendations, but in most cases the intervals have not been shortened, thanks in part to the new CI-4 motor oil. But if extended drain intervals are attempted, they must be accompanied by regular oil analysis.

"Keep the level of the coolant up, because the EGR cooler is rather high in the cooling system and doesn't like low coolant levels," Wildman says of International's VT-365, but it's also true of other EGR'd diesels. "Air bubbles can form, which would be hard on the [EGR] cooler, and of course other things in the system."

At times, the cooling systems will run 10 to 30 degrees hotter, so the additive package in the cooling system must be kept up to spec so the coolant stays strong. Be sure clamps and hoses are healthy, and replace them at the first sign of weakness in metal or rubber.

Keep all heat exchangers clean and free of bugs and dirt, Fancher advises. The bug screen should be frequently pressure-washed, and the radiator and aftercooler washed as needed, especially in construction trucks, which can pick up dirt and debris on work sites.

Truck Image
Builders are ready to sell you new trucks that should prove to be reliable and economical.
Builders are ready to sell you new trucks that should prove to be reliable and economical. But if you'd rather wait and see how the EGR'd diesels work out, there's probably plenty of life left in what you have.
About 2,500 Detroit Diesel Series 50 engines with EGR have been in tough, stop-and-go service in city transit buses since early 2000 and are performing well. Turbocharger shaft failures were common at first, but were corrected under warranty and affected non-EGR turbos, too, say bus fleet managers we talked to. Engineers have also modified electronic controls and some sensors. Four-cylinder, 8.5-liter engines accelerate fast and fuel economy is good, managers report. S50's EGR system is essentially the same as on new Series 60 truck engine.
The labels show principal elements of V-Pulse EGR system on Volvo's VED12. None require any special maintenance, the builder says.
Serious About Warranties

Cummins provides a new Uptime Guarantee Program for its ISX and ISM diesels produced between Oct. 1 and next March 31. "If an engine fails for any reason, not just the EGR system but for any reason, Cummins will guarantee that the engine will be repaired in 24 hours or less, or we will supply a replacement vehicle," says Tom Kieffer, executive director for marketing.

That promise is good for two years or 250,000 miles for highway trucks and an equivalent period for vocational trucks. Extended warranties for up to 500,000 highway miles are available for $800 to $1,800. Truck owners must go to Cummins distributors for any work.

Paccar, owner of Kenworth and Peterbilt, offer no-extra-cost warranties that cover major components of EGR'd Cummins ISX and ISM engines for five years or 150,000 miles for vocational trucks and five years/500,000 miles for highway trucks. They must be bought by Dec. 31, and work would be done at truck dealers.

Kieffer says the new warranties are the result of 'misperceptions that our new products have not been adequately tested." On-road testing has accumulated millions of miles, and "Cummins' EGR subsystem will have more test miles and hours than any subsystem Cummins has ever introduced."

Electronic Watchdogs

In all EGR'd diesels, the special parts are monitored by the engines' electronic controls, which will flash warnings and diagnostic codes in case of malfunctions. Electronic memories will record malfunctions for attention by technicians. Tampering will not be tolerated, as disconnecting or removing EGR parts will render the engine non-operable or cause it to go into "limp" mode. This reduces power and will shut down the engine.

Even if an engine would run after stripped of its EGR gear, it might eventually be caught at a roadside inspection. Led by California, authorities in various states are checking exhaust emissions to be sure operators are complying with the letter and spirit of Clean Air laws.

Keep the Older Stuff?

None of the EGR issues need concern an operator who buys used trucks, or intends to keep what he has for some time. Depending on geographical areas and time of year, good used vocational trucks can be scarce. But there are still lots full of former highway tractors that, even with big sleepers, can be bought cheaply and run locally, perhaps pulling end-dump or equipment trailers.

Some truck models, such as Peterbilt's 377, 378 and 379 and Kenworth's W900B and T800, have sleeper boxes that can be pulled off and the cabs enclosed for $2,500 or so. Any tractor with a separate sleeper box is likewise convertible.

And there's nothing stupid about squeezing all the life possible from existing trucks. Most construction truck operators run their trucks for a long time, and this has become easier as major components in Class 8 trucks are made to run the equivalent of 1 million or more highway miles.

They will need regular work along the way. Plan on that and you could say, "What's all the fuss over those new engines?"

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