April 2012, TruckingInfo.com - Feature by Deborah Lockridge, Editor in Chief, Editor-in-Chief
Extended drain intervals don't mean you can ignore the truck in between oil changes.
Many newer engines already have longer oil drain intervals than in the past, with some up to 40,000- to 50,000-mile drains for on-highway applications.
There are a lot of fleets that "have an old-school mentality about changing their oil every 10,000 or 15,000 miles," says Bruce Stockton, longtime maintenance manager at Contract Freighters Inc./Con-way Truckload and now a consultant at Stockton Solutions. "They're really just wasting a resource when they do that." Of course, extending oil drain intervals is always a balancing act. Just because you don't have to bring in the truck for an oil change for 50,000 miles or more doesn't mean you don't need to get your hands on it more frequently, to lube chassis components or perform oil analysis or regular inspections.
It's very important when looking at drain intervals to consider your particular application. Tom Pratt, a trainer at Penn Power Group, a member of the WheelTime Network, says Detroit recommends oil drain intervals based on whether the truck is in long haul, short haul or severe duty. If you're running a dump truck, he says, you could be running 40,000 miles a year, which would, by mileage, put you in the short-haul category. However, if you're running in heavy dust conditions, that's going to still classify it as severe duty and mean shorter oil drain intervals.
Enter the filter Oil filters play an important role here. Longer oil drains could mean a need for a more robust filter, and some filters are specifically marketed as being able to help extend drain intervals.
The first rule of selecting an oil filter is to choose one that meets the engine manufacturer's minimum specifications. Make sure you cross-reference the part number in a cross-reference chart. Many filter makers offer easy cross-reference look-ups online.
"When a customer goes to purchase an oil filter element from a source other than an OEM, they are taking a chance that it doesn't meet all of the OEM requirements, of which efficiency is only one of several," says David Cline, product manager, oil filtration systems for Racor Filtration.
"Element performance, which includes micron ratings, is important when going outside of the OEM-supplied filter for cost reasons or when there is a need to have performance beyond the norm." As Stockton explains, "If you had an engine go down and [the engine maker] determined it was the result of poor filtration, and that filter wasn't on their approved list, they could, and in some cases did, deny coverage under warranty." Even if the engine's no longer under warranty, you're more likely to protect the engine properly if you stick to those specs. You may even want to go beyond them if you're extending drains.
For instance, Cline explains, if you buy a filter that says it has a very high efficiency but don't consider its capacity, that filter may not have the contaminant-holding ability needed to perform properly throughout the extended drain interval.
"If you want to double your service interval, then you, in essence, need to double the amount of contaminants the filter can collect before it reaches the end of its life," says Jim Watson, director of engineering for liquid engine and filtration at Donaldson. A traditional cellulose based filter may not do the job; you may need to move into filters with a synthetic media, says Watson's colleague, Rod Radosevich, engine marketing manager.
Jim Gambill, Delo brand manager at Chevron Lubricants, says in testing, "we have seen that in some cases, the same filters simply won't hold up for the extended service intervals." Time for chemistry class Some suppliers offer filters they say take more soot and other contaminants out of the oil to help it last longer. However, contaminants and soot are only one piece of the puzzle when it comes to oil protecting your engine.
"Removing a smaller solid piece of particulate does not change the rate at which the oil oxidates or the [additive] depletion rate," says Paul Bandoly, manager of technical services and customer training at Wix Filters. "Contaminant control is important for engine wear but not necessarily for oil life." Engine oils are formulated with a complex balance of chemicals that perform functions such as neutralizing acids and preventing oxidation.
Let your oil go too long without changing, and those additives break down. When this happens, not only is the oil not doing as good a job of protecting, cooling and cleaning your engine, but you also may see filter plugging. If you overuse the oil to the point that the additive package drops out and forms sludge, Baldwin Filters says in a technical bulletin, it can plug not only filters but also engine passages.
That's why some filters aimed at extended drain intervals "re-additize" the oil, replenishing the protective chemicals. However, this practice is frowned on by some.
"Engine oils must go through a costly and extensive testing protocol to meet API licensing approvals," says Mark Betner, heavy-duty lubricants manager at Citgo. Those API classifications set chemical limits that are important for exhaust emission compatibility and overall performance.
"How does adding additional additives along the way impact the formula and/or change the original formula?" Too much additive of one type, say detergents or dispersants, can create unwanted consequences. "Adding more of this product raises ask level, which can shorten the life of the diesel particulate filter," says Chevron's Gambill.
Brad Williamson, manager of engine and component marketing at Daimler Trucks North America, says filters with need-release additives typically address only depletion of TBN (the acid-neutralizing chemicals and a key limiter to engine oil life). He says most don't help with additives that address other areas of degradation, such as oxidation and nitration.
Dave McKenna, director of Mack powertrain sales, says his company has tested some additized filters with mixed results. "Some positive, some with little effect," he says.
"We agree with the oil companies that you don't want to dump additives into the oil willy-nilly," says Kevin Kroger, president of bypass filter maker Puradyn. He contends that some systems dump additives into the oil too quickly. "The release of additives into the oil has to be precise." His company, he says, has developed a way to release those additives more slowly.
At least one maker of a bypass system that additizes the oil says its product can only be used in pre-EPA 2007 engines. Newer engines require oil meeting API's CJ-4 standards; they feature lower ash and other changes needed to work with diesel particulate filters.
If you choose to use a filtration system that introduces fresh additives into the oil, make sure it's designed to work with the oil specification you're using, and check with your engine manufacturer representative.
One recent introduction to the market tackles the extended-drain and additive question differently. Wix says its EcoLast filter can double oil drain intervals because a chemical structure within its synthetic media sequesters the acid from the oil and traps it in the filter. It's not adding any chemicals but simply helping the oil's own additives last longer.
Again, keep in mind that acid control is not the only factor. Oil analysis is a must to keep an eye on the additive levels with any extended-drain program.
Makers of aftermarket supplemental filtration systems say they can extend your oil drain intervals and potentially extend engine life by super-filtering the oil. Opinions on these vary widely. In general, it appears that severe-duty applications are more likely to benefit from bypass filtration than typical on-highway
In my column entitled Changing Oil Preference? (Machinery Lubrication, September-October 2004), I reevaluated my long-held convictions for recommending mineral-based oil over synthetic. While writing the article, it occurred to me that I should look at oil filters more closely and with an open mind. Filters are an integral part of the oil cycle in an engine. If I were changing my mind about what lubricant to recommend, I should also reevaluate my oil filter recommendations.
Automotive oil filters fall into two categories, full-flow and bypass.
Bypass oil filters take about 10 percent of the oil pumped from the sump, filter it and then return it to the sump while the remaining 90 percent is delivered to the lubricated components. Full-flow oil filters filter 100 percent of the oil pumped before it continues on to the lubricated surfaces. It might seem that the full-flow filter would be the best oil filter, though that is not necessarily true. Each has its virtues and vices.
No Oil Filter Early car engines did not employ oil filters. The forerunner to oil filtration was mesh and screen strainers. I don’t consider screen or mesh to be an effective filter. There were cars manufactured through the late 1960s that did not have oil filters at all. (Anyone have a 1960smodel Volkswagen or Fiat?) The first VW I saw with an oil filter was the water-cooled VW Rabbit in 1975. The VW Super Beetle had a full-flow filter after 1972 until production stopped in 1980. There was also a full flow filter on the 1975 VW sedan and the 1980 VW convertible.
Bypass Oil Filters Bypass oil filters were the first oil filters on cars. They’ve been installed on cars and light trucks since the early 1920s. Ernest Sweetland introduced the first modern oil filter which promised pure oil later? so named because it was located between the pump and the sump, and it promised to deliver the pure oil later to the bearing surfaces.1 The filter was a heavy metal case; inside was a series of metal plates with twill weave material around each plate. A sight glass let the user know when the oil flow dwindled to a trickle. At this point the whole filter unit, case, sight glass, plates and twill material had to be replaced. This was the beginning of the Purolator oil filter company.
Mr. Sweetland’s filter was improved by introducing replacement cotton fiber filtration in the late 1930s, which could be changed without replacing the whole filter unit. However, it remained a bypass oil filter, where 90 percent of the oil was sent to the engine unfiltered. As long as the oil contamination rates were low and the oil was changed frequently, the bearings had some reasonable life expectation. Most automotive oil filters were the bypass-type until the mid-1940s.
In a previous column, I wrote that 45 years ago an engine could run 100,000 miles before needing an overhaul (Machinery Lubrication, July-August 2001). All the engine required was care and persistent maintenance. In that age of $2,000-cars and oil costing $0.25 per quart, oil filtration methods and schedules were doing a fiscally responsible job. By 1950, most new cars were built with full-flow filters. The increased use of full-flow oil filters accompanied a decrease in bypass filter application.
Full-flow Filters What was the reasoning for the shift to full-flow filters? It?s simple - all the oil, not the 10 percent of bypass norms, was filtered before it was sent to the oil gallery. Ideally, we would like to see particles somewhat smaller than five microns trapped by the oil filter, however, there are typically price and performance trade-offs with finer filtration.
Judging a filter only by its micron-size trapping ability has its limitations. My barbeque grill will filter five microns; a few five-micron particles will catch on the grill as fluid passes over. The SAE HS806 standard uses both a single-pass test and a multipass test, assessing dirt-holding, contaminant capacity in grams, and efficiency based on weight. The efficiency of the filter is determined by weight only through gravimetric measurement of the filtered test liquid. Typical numbers for cellulose paper filter elements are 85 percent (singlepass) and 80 percent (multipass).
The SAE J1858 test provides both particle counting and gravimetric measurement to measure dirt-holding capacity and capture efficiency.
Actual counts of contaminant particles by size are obtained every 10 minutes, both upstream (before the filter) and downstream (after the filter), for evaluation. From this data, a filtration ratio and capture efficiency above different contaminant particle sizes can be determined as well as dirt-holding capacity and pressure drop as a function of time. Typical numbers for paper element filters are 40 percent capture efficiency at 10 microns, 60 percent at 20 microns, 93 percent at 30 microns, and 97 percent at 40 microns.
Oil filter design is somewhat of a balancing act between particulate size, filter medium, surface area of filter medium and oil pressure. The finer the filter medium, the shorter a filter?s lifespan before it begins to show pressure drop and the oil filter bypass valve is opened. However, new synthetic filter media and pleating configurations have managed to overcome some of these drawbacks. We have the capacity to filter out particles smaller than needed (less than two microns) to protect the oil between bearing surfaces but determining the right balance can be a real puzzle.
The original full-flow filters were housed in heavy canisters. The element was changed, the canister was cleaned, and a new sealing ring was installed. In about 1955, however, the full-flow filter as we recognize it today was introduced. Within a few years, almost all cars featured the present-day disposable, spin-on filter with a lightweight canister and its own sealing ring.
Choosing a Filter - Full-flow or Bypass Bypass filters are not new to the automotive environment. They were the first filters installed on cars but have since been replaced by full flow filters on almost 100 percent of the new cars manufactured today.
I am, however going to vote for both types of filters; each stands out in certain conditions. Ford Motor recently announced that it is equipping its 2005 E Series with bypass filtration.
I am a big advocate of oil coolers to help ease the burden on the lubricant. Cars last longer with oil coolers. Cars last longer with better filtration and timely oil and filter changes. Cars last longer with cleaner oil. The trucking industry is ahead of the auto industry on recognizing the importance of cleaner oil. There is, in the trucking industry, a reasonable expectation of 500,000 miles between major overhauls.
Why the long interval? Truck manufacturers use both bypass and full flow filters, oil coolers and transmission coolers. In short, they use it all and have the results to justify their expenditure. One million miles between overhauls is no longer rare in the trucking industry.
With the replacement cost of my wife’s 1998 Buick Park Avenue approaching $35,000 I need to make that car last as long as I can. Any reasonably priced device that would extend its life beyond 200,000 miles (it is currently at 88,000 miles) is of interest, and is financially beneficial to me. Some of the advertisers in ML make or sell bypass filters for modern automobiles.
There are now oil filter units commercially available for passenger cars that employ both the bypass and full-flow filters. I’ve found a neat place under the hood of the Park Avenue to mount the manifold and filters. I think I will check the dimensions one last time and purchase one.
Final Note Any dirt that gets past the air filter enters the engine, becoming the enemy of all lubricated components. This makes the oil filter’s job more challenging. To combat such wear, change your air filter regularly.
PCV System - A Breath of Fresh Air? (Machinery Lubrication, September-October 2001) discusses maintaining the PCV If damaged, it can be another source of engine damage.
Nov 8, 2012 12500 am
First off, all oil breaks down. That generally will include basestocks and additives. Without focusing on performance characteristics, the most significant difference from one oil to another is how quickly breakdown occurs. Although there are many factors that contribute to the breakdown of an oil, heat is one of the most important. Depletion and decreased effectiveness of oil additives is also important, but that will be discussed later.
Petroleum oil begins to break-down almost immediately. A high-quality synthetic, on the other hand, can last for many thousands of miles without any significant reduction in performance or protection characteristics. Synthetics designed from the right combination of basestocks and additives can last almost indefinitely with the right filtration system.
Flash point is the temperature at which an oil gives off vapors that can be ignited with a flame held over the oil. The lower the flash point the greater tendency for the oil to suffer vaporization loss at high temperatures and to burn off on hot cylinder walls and pistons.
The flash point can be an indicator of the quality of the base stock used. The higher the flash point the better. 400 degrees F is the absolute MINIMUM to prevent possible high consumption.
Even the best petroleum oils will have flash points only as high as 390 and 440 degrees F. Some actually have flashpoints as low as 350 degrees. For today’s hot-running engines, this is not nearly enough protection. Just about any synthetic you come across will have a flashpoint over 440 degrees. Premium synthetics can have flashpoints over 450 degrees F with some even reaching as high as 500 degrees F. Thatʼs a big difference.
Itʼs important to understand how petroleum and synthetic oils burn off.
As a refined product, petroleum oil molecules are of varying sizes. So, as a petroleum oil heats up, the smaller, lighter molecules begin to burn off first.
Since the ash content in many petroleum oils is higher than synthetics, deposits and sludge are left behind to coat the inside of your engine.
Detergent and dispersant additives are used to keep these deposits to a minimum, but only so much can be done. Unless youʼre changing a petroleum oil every 2,000 to 3,000 miles some deposits are going to be left behind.
In addition, as smaller particles burn off, the larger, heavier molecules are all that is left to protect the engine.
Unfortunately, these larger particles do not flow nearly as well and tend to blanket engine components which just makes the heat problem worse.
Synthetic oils, on the other hand, because they are not purified, but rather designed within a lab for lubrication purposes, are comprised of molecules of uniform size and shape. Therefore, even if a synthetic oil does burn a little, the remaining oil has nearly the same chemical characteristics that it had before the burn off. There are no smaller molecules to burn off and no heavier molecules to leave behind.
Moreover, many synthetics have very low ash content and little if any impurity. As a result, if oil burn off does occur, there is little, or no ash left behind to leave sludge and deposits on engine surfaces.
Obviously, this leads to a cleaner burning, more fuel-efficient engine.
Synthetics do a much better job of “cooling” engine components during operation. Because of their unique flow characteristics, engine components are likely to run 10 to 30 degrees cooler than with petroleum oils. This is important, because the hotter the components in your engine get, the more quickly they break down.
Most people understand that at cold temperatures, an oil tends to thicken up, and many people know that synthetics do a better job of staying fluid. However, many people don’t realize why petroleum oils tend to thicken up. More importantly, though, they don’t realize that this thickening process can wreak havoc on their oil. Because most petroleum oils contain paraffins (wax), they tend to thicken up considerably in cold temperatures. Therefore, in order to produce a petroleum oil that will perform adequately in severe cold temperatures, additives called pour point depressants must be used in high quantities. These additives are designed to keep the wax components of a petroleum oil from crystallizing. This maintains decent flow characteristics in cold weather for easier cold starts.
In areas where the temperature remains below zero for any period of time, these additives are used up very quickly because petroleum oils are so prone to wax crystallization. As a result, the oil begins to flow less easily in cold weather temperatures. Of course, the result is harder cold starts and tremendously increased engine wear. Thus, the oil must be changed in order to provide the cold weather engine protection that is necessary.
Synthetic oils, on the other hand, contain no paraffins. Therefore, they need NO pour point depressant additives. In addition, even without these additives, synthetics flow at far lower temperatures than petroleum oils. For instance, very few petroleum oils have pour points below -30 degrees F. Many synthetic oils, without any pour point depressants, have pour points below -50 degrees F. That’s a big difference. There is, in fact, one oil on the market that has a pour point of -76 degrees F.
Since synthetics do not have any pour point depressants, there is no chance of these additives breaking down or being used up over time.
There are no additives to break down. Therefore, synthetic oils maintain their cold temperature flow characteristics for a very long time. As a result, there is one less reason to change the oil if using synthetic as opposed to petroleum.
Another part of cold weather driving that is extremely tough on an oil is condensation. Because it is so cold, it takes a fairly long drive to get the engine warm enough to burn off the condensation that occurs inside the engine. Consequently, vehicles routinely driven short distances in cold weather will build up condensation within the oil. If left to do its dirty work, this water would cause acids to build up within the oil and corrosion would begin within your engine.
So, there are additives in the oil that are designed to combat these acids. Generally, the TBN value of an oil will be a good determination of how well and for how long an oil will be able to combat these acids.
Most petroleum oils have TBN numbers around 5. Most synthetics have TBN levels over 8 or 9. Premium synthetic oils (especially those designed specifically for extended oil drains) will have TBN numbers around 11 to 14. This allows for much better acid control for a much longer period of time, thus decreasing the need for an oil change due to cold temperature condensation.
It is true that the additives in many oils begin breaking down after only a few thousand miles. What needs to be recognized is that there are different quality “grades” of additives just as there are different quality grades of just about any other product that you buy. There are also different combinations of additives that tend to work for better and for longer when combined than when used individually.
VISCOSITY RETENTION – Shear stable viscosity index improvers help premium synthetic motor oils maintain their viscosity in the range appropriate to each grade over extended drain use. Conventional oils formulated with easily sheared viscosity index improvers often drop out of viscosity specification relatively quickly – sometimes even before the end of a 3,000-mile oil drain interval. Viscosity loss leaves oils incapable of protecting engines from metal to metal contact and wear in high temperatures.
CONTAMINANT CONTROL – Dispersants keep contaminants, including combustion by-products, suspended in oil. The rate of dispersant depletion depends on the motor oils additive treat-rate and the oils contaminant load. Premium synthetic motor oils are formulated with high additive treat rates specifically to allow extended drain intervals.
ACID CONTROL – Total Base Number (TBN) describes the acid neutralization ability of an oil, with higher TBN oils providing longer lasting acid neutralization. Most passenger car motor oils are formulated with TBN of 5 to 7. Many synthetic motor oils are formulated with 9-11 TBN or higher. The result: longer and better acid neutralization capability allowing for extended drain use.
There is also the issue of contamination. Oil will be contaminated in three major ways.
One will be through debris that comes in through the air intake. Once it makes it through the air filter, it ends up in your oil. Once in your oil, it starts damaging your engine.
The second source of contamination will be metal shavings from the inside of your engine. The lesser the quality of the oil, the higher percentage of these shavings because there will be more metal to metal contact inside the engine.
The third source of contamination will be from combustion byproducts.
Combustion by-products will generally raise the acidity of your oil, which causes corrosion in your engine. In addition, they will be left behind as the engine oil burns off and will collect on the inside of your engine as deposits. To maintain the viability of your oil as well as protection of the engine, the contaminants have to be removed/ neutralized.