A teaspoon of dust circulating throughout your engine oil is enough to cause premature wear – a handful will destroy an engine. A mere pinch of dust can sandblast the insides of your hydraulic system and a speck or two of microscopic grit can ruin high-pressure fuel injectors.
Your machines may work in the dirt and dust all day, but keeping the internal components clean and free from contamination is one of the most important things you can do to prolong the life of your equipment. And engines, hydraulic systems and fuel injection systems have changed so much in the past few years it’s critical you understand the new requirements for a successful filtration program.
With the exception of Caterpillar’s ACERT engine design, all the new, emissions-compliant Tier 2 and Tier 3 engines use some form of EGR or exhaust gas recirculation. In order to meet the Environmental Protection Agency’s clean air standards, these EGR engines redirect a certain portion of the diesel exhaust back into the engine for further combustion. This recirculation of the exhaust gas is great for reducing emissions, but the stuff that doesn’t go into the air winds up in your engine oil. This is soot primarily, but the EGR process also raises oil acid levels and engine temps.
Oil manufacturers have developed new formulations to help neutralize these problems, but filters play a role too. Several OEMs and filter manufacturer’s have come out with filters with centrifugal elements that spin the contaminated lube oil, forcing the heavier soot particles to the outside of the element where they can be captured and removed from the oil. Some centrifuges are separate components, but there are also designs that incorporate an integral centrifuge in a spin-on canister.
If soot in the engine oil is going to be a condition you need to monitor, it would be a good idea to add a particle count to your oil analysis reports. Particle counts aren’t normally included on heavy equipment oil analysis, but given the increase in soot coming from EGR engines, it’s best to test for it.
The increased acidity and heat found in EGR engines has also inspired some filter manufacturers to offer filters with additive replacement packages. These filters put back into the oil certain additives that are depleted in the EGR environment, making it possible to maintain or extend oil drain intervals.
EGR or not, fuel injection pressures have increased considerably over the past few years, making it imperative that you use high quality fuel filters and fuel-water separators. The same holds true for high-pressure hydraulic systems and filters for hydraulic fluid. What was considered an acceptable level of contamination in fuel and hydraulic systems five years ago can be extremely destructive today. As a general rule today, most OEMs are recommending fuel filtration in the range of 2 to 5 microns and hydraulic fluid filtration down to 5 to 30 microns. (For comparison’s sake, the average lube oil filter takes out particles down to 40 microns and the thickness of a human hair is around 80 microns.)