PwrSmoke
Full Access Member
I routinely run 3-4 year OCIs on my equipment. It was not done willy-nilly, either. I would run a year, then have the oil tested. Then run two, three, etc. I'm on the fourth year for the fill in my '86. At this point, I use only miles or hours on all the equipment I maintain (a car, two trucks, two farm tractors, riding mower, lawn tractor, a generator and several other devices powered by small engines), up to a specific limit of five years. That five year limit is somewhat arbitrary, mostly because that's the farthest limit I have tested personally. You can find examples of much longer intervals , some from sources I am inclined to trust, but because it's my stuff, I prefer to generate my own data.
Bottom line... oil cannot read a calendar. Environmental and operational conditions can and will dictate the time part of the OCI. Repeated short hops (1-5 miles) where the oil does not get warmed up, extended cold weather operation, will deplete the additive package quickly. Poor storage conditions, i.e. condensation, will have an effect as well. But if the truck is driven to the point of heating the oil up and keeping it hot for a minimum of 15 minutes regularly (not necessarily frequently), that's more than enough to keep the oil healthy over the long haul. A guy in Texas posted a UOA (Used Oil Analysis) on a well known oil geek site for a tractor that had sat in a barn for 30 years. The oil was still suitable for use by an objective standard. There are many other such examples documented my science and technology if you search and look beyond unsubstantiated anecdotes or folklore.
Some will ask, "Why do the car manufacturers say X months or years then?" A fair question with several answers:
1) CYA- They need a lot of safety factor in their recommendations to account for a very broad average of climate, storage conditions, operational conditions, maintenance (or lack thereof), quality of oil used, etc. They figure a worst case scenario combination of the things I listed above, and more besides, and recommend appropriately. When you get very specific. you can fine tune alot. Most often, that results in a longer interval but sometimes shorter.
2) Sell, sell, sell! It doesn't hurt your truck to change the oil more often than it truly needs but it enhances the finances of the people who sell maintenance products or services. In the commercial world, that's what they call a SCORE.
3) The one benefit of arbitrary oil change intervals is that it gets the car in for other checks and service. The "unwashed masses" (those who are not gearheads and do not maintain or repair their own equipment) tend to regard a long OCI as a license to neglect their cars. The car doesn't get in for the other stuff, tire pressure checks, tire rotation, a look at the fan belts, a look at the air filter, a look for signs of upcoming trouble, etc. The time interval has some value when looked at in that light... for the great unwashed masses. Not for us, who presumably look at stuff often. Some of us are oil nerds and take this to ridiculous extremes. Heck, I'm so oil-nerdy-sick that I calculate the operating viscosity of the oil as I go down the road by watching the oil temp and oil pressure gauges (yes, you can do that!). You don't have to be a total oil geek, though, to know the cause and effect of different operating conditions on the oil and adjust the OCI to suit.
There are two primary reasons to change oil:
1) Contamination, including what's built into the oil (no, oil is not spotlessly clean when new), wear or break in metal (wear metals inputs are low in a broken-in engine but break-in wear metals can be extensive), soot and combustion byproducts, dirty air from poor air filtration (which gets past the rigs to contaminate the oil, plus it gets in thru crankcase breathers... especially road draft tubes). Much contamination can be filtered, read on.
2) Additive package depletion. The additive package depletes itself most rapidly when combating high contamination levels and acidic conditions that come from the combustion process and contamination. If you minimize the contamination inputs, the oil additive package can last a very long time.
Ways to Extend Oil Life, By Order of Importance (IMO but a pretty generally accurate standard in the industry)
1) Improve air filtration. The intake is the biggest source of outside contamination into the engine. Think of it. Your engine is sucking in an average of 200 cubic feet of air per minute. That air is laced with particles, most of which are harmful to the engine in some way. An "average" air filter can remove about 90-95 percent of them (when judged on a test standard using fine dust, which is more real world than the coarse standard that is common in advertising). So five percent of that material is getting into the engine and think of how much that could be over hours and hours of run time. So, you run a very efficient air filter, even if it costs you a little power due to flow (we could have a LONG discussion here), you eliminate all the other ways dirt can get into the crankcase (breather hoses, oil cap, CDR, leaking valley pan, road draft tube if so equipped, etc.), and you have eliminated the majority of the contamination inputs for the engine. The additive package then has an easy job and depletes slowly. Bear in mind that really dirty air from little or no filtration can have rapid if not immediate effects on engine life as well as long term. IT'S IMPORTANT!
2) Improve oil filtration. A broken in engine with no problems, generally clean oil generates comparatively little wear metal. Soot agglomeration is always a problem for diesels. It starts out very fine and oil filters can't catch much of it until it agglomerates (wads up into sludge). Agglomeration occurs when the dispersants in the oil are depleted. Until that happens, the soot particles stay small and generally are too small to be harmful individually (though they make the oil black). Soot is often submicronic (smaller than one micron) but can be in the 1-5 micron range. Stuff below 10 microns is generally considered "not harmful" as long as there is not a high concentration of it. A normal oil filter can catch most of the normally generated wear contamination (less wear from cleaner oil) but because a specific amount of oil flow is needed for lubrication, it's difficult to find room for a highly efficient oil filter that will have the flow and capacity needed to filter below about 20 microns absolute (absolute= about 98 percent of the contaminants above the micron rating when measured in a specific multi-pass test). When you increase efficiency, you need to increase the amount of media to maintain flow and capacity. Synthetic media filters are best for combining flow, capacity and pore size (the ability to trap smaller particles). Bypass filtration (which filters a small amount of oil flow very finely in a second filter) can help oil life by removing soot and even smaller wear or contamination particles without effecting flow. Some bypass filtration can also trap moisture and the precursors to sludge. Serious improvements to oil filtration can be EXPENSIVE, so you have to balance and amortize that cost by extending the OCI of the oil. Yes, improved filtration does improve engine life but it's not by a huge factor (despite the ad hype you see... you have to look close at the test data because it often measures wear of highly filtered oil against a crankcase full of highly contaminated oil, not the type of oil that you would normally let remain in your engine).
3) Improve the oil. A stronger additive package lasts longer in any operating condition. The base oil (i.e. synthetic vs conventional) is less important from this standpoint because it has little effect on how long the additives can do their jobs. A slippery syn base oil can reduce wear, and that helps, but the difference in wear between a syn and good conventional is not huge.
If you have to pick one thing to improve, my advice is to pick the air filter (and related crankcase breathers). Again, that is the source of 90 percent of engine contamination. Make sure the filter housing seals well to the intake. Make sure the filter seals in the housing well (use filter grease for sealing). Duct the intake hose to the cleanest source of air (generally the stock location). Make sure your CDR drain seals well in the valley pan or valve cover and the o-ring into the intake is good. Make sure there is a good seal on your oil cap. If you have a turbo, make sure your many intake clamps are tight (sues some sealer on the hoses). If you have a road draft tube, go back to a CDR or some other sealed breather. There are better and worse air filters out there but that's a LONG discussion. In general, if you by the premium level filter (most brands have the cheap price point "bronze" filter then "silver" or "gold" you get the idea), it will have better, more efficient media. I have seen testing that indicates this. Avoid oiled cotton gauze, foam (unless backed up by other better media) or oil bath filter media because they can be very inefficient.
You can improve oil filtration effectively and economically by using the Powerstroke oil filter, which is more efficient (19 micron nominal vs 28 nominal generally). The Powerstroke spec'ed a more efficient filter because of HUEI and that increase translates to all the brands that make filters for the application. On top of that, the PSD filter has about twice the media, so you can run it lots longer. There are high dollar synthetic oil filter out there that cost about twice as much as a regular filter. They are very efficient, long lasting and good but the numbers don't always crunch unless you run an extended OCI.
Finally, I've given you a lot of generalities above but if you want to go really long on the OCI, the only way to judge how long YOUR oil can go in YOUR individual conditions is via oil analysis. If you want to play this game bigtime, you gotta learn the rules. To be honest, until you do your testing, it will be MORE expensive to chart your way than just to dump the oil arbitrarily and be done with it. IMO you can safely extend to two or three years 6-8,000 miles pretty easily with minimal testing but there are still a LOT of variables. I suggest a first step is to get an oil sample (google Blackstone Labs) according to solid sampling guidelines when you do your next OCI. Don't look at it as a guide to engine condition (you can't get that from one sample), just oil health. Pay extra for the TBN test. That test tells you how much of the additive package is left. If your test is like most and you are doing short (4,000 miles or less) OCIs, you will probably find you were dumping oil with a LOT of life left.
Since winter is here, another tip. Plugging the truck in is conducive to longer oil life (and better mpg) because it gets the oil warmed up faster. Our engines have an advantage in that the oil cooler is also an oil warmer so warmer water in the cooling system get the oil warmer sooner. Vs some other engines I have seen or owned, the oil temp on my IDI reaches a warmed up state much faster. And that's a GOOD THING!
Bottom line... oil cannot read a calendar. Environmental and operational conditions can and will dictate the time part of the OCI. Repeated short hops (1-5 miles) where the oil does not get warmed up, extended cold weather operation, will deplete the additive package quickly. Poor storage conditions, i.e. condensation, will have an effect as well. But if the truck is driven to the point of heating the oil up and keeping it hot for a minimum of 15 minutes regularly (not necessarily frequently), that's more than enough to keep the oil healthy over the long haul. A guy in Texas posted a UOA (Used Oil Analysis) on a well known oil geek site for a tractor that had sat in a barn for 30 years. The oil was still suitable for use by an objective standard. There are many other such examples documented my science and technology if you search and look beyond unsubstantiated anecdotes or folklore.
Some will ask, "Why do the car manufacturers say X months or years then?" A fair question with several answers:
1) CYA- They need a lot of safety factor in their recommendations to account for a very broad average of climate, storage conditions, operational conditions, maintenance (or lack thereof), quality of oil used, etc. They figure a worst case scenario combination of the things I listed above, and more besides, and recommend appropriately. When you get very specific. you can fine tune alot. Most often, that results in a longer interval but sometimes shorter.
2) Sell, sell, sell! It doesn't hurt your truck to change the oil more often than it truly needs but it enhances the finances of the people who sell maintenance products or services. In the commercial world, that's what they call a SCORE.
3) The one benefit of arbitrary oil change intervals is that it gets the car in for other checks and service. The "unwashed masses" (those who are not gearheads and do not maintain or repair their own equipment) tend to regard a long OCI as a license to neglect their cars. The car doesn't get in for the other stuff, tire pressure checks, tire rotation, a look at the fan belts, a look at the air filter, a look for signs of upcoming trouble, etc. The time interval has some value when looked at in that light... for the great unwashed masses. Not for us, who presumably look at stuff often. Some of us are oil nerds and take this to ridiculous extremes. Heck, I'm so oil-nerdy-sick that I calculate the operating viscosity of the oil as I go down the road by watching the oil temp and oil pressure gauges (yes, you can do that!). You don't have to be a total oil geek, though, to know the cause and effect of different operating conditions on the oil and adjust the OCI to suit.
There are two primary reasons to change oil:
1) Contamination, including what's built into the oil (no, oil is not spotlessly clean when new), wear or break in metal (wear metals inputs are low in a broken-in engine but break-in wear metals can be extensive), soot and combustion byproducts, dirty air from poor air filtration (which gets past the rigs to contaminate the oil, plus it gets in thru crankcase breathers... especially road draft tubes). Much contamination can be filtered, read on.
2) Additive package depletion. The additive package depletes itself most rapidly when combating high contamination levels and acidic conditions that come from the combustion process and contamination. If you minimize the contamination inputs, the oil additive package can last a very long time.
Ways to Extend Oil Life, By Order of Importance (IMO but a pretty generally accurate standard in the industry)
1) Improve air filtration. The intake is the biggest source of outside contamination into the engine. Think of it. Your engine is sucking in an average of 200 cubic feet of air per minute. That air is laced with particles, most of which are harmful to the engine in some way. An "average" air filter can remove about 90-95 percent of them (when judged on a test standard using fine dust, which is more real world than the coarse standard that is common in advertising). So five percent of that material is getting into the engine and think of how much that could be over hours and hours of run time. So, you run a very efficient air filter, even if it costs you a little power due to flow (we could have a LONG discussion here), you eliminate all the other ways dirt can get into the crankcase (breather hoses, oil cap, CDR, leaking valley pan, road draft tube if so equipped, etc.), and you have eliminated the majority of the contamination inputs for the engine. The additive package then has an easy job and depletes slowly. Bear in mind that really dirty air from little or no filtration can have rapid if not immediate effects on engine life as well as long term. IT'S IMPORTANT!
2) Improve oil filtration. A broken in engine with no problems, generally clean oil generates comparatively little wear metal. Soot agglomeration is always a problem for diesels. It starts out very fine and oil filters can't catch much of it until it agglomerates (wads up into sludge). Agglomeration occurs when the dispersants in the oil are depleted. Until that happens, the soot particles stay small and generally are too small to be harmful individually (though they make the oil black). Soot is often submicronic (smaller than one micron) but can be in the 1-5 micron range. Stuff below 10 microns is generally considered "not harmful" as long as there is not a high concentration of it. A normal oil filter can catch most of the normally generated wear contamination (less wear from cleaner oil) but because a specific amount of oil flow is needed for lubrication, it's difficult to find room for a highly efficient oil filter that will have the flow and capacity needed to filter below about 20 microns absolute (absolute= about 98 percent of the contaminants above the micron rating when measured in a specific multi-pass test). When you increase efficiency, you need to increase the amount of media to maintain flow and capacity. Synthetic media filters are best for combining flow, capacity and pore size (the ability to trap smaller particles). Bypass filtration (which filters a small amount of oil flow very finely in a second filter) can help oil life by removing soot and even smaller wear or contamination particles without effecting flow. Some bypass filtration can also trap moisture and the precursors to sludge. Serious improvements to oil filtration can be EXPENSIVE, so you have to balance and amortize that cost by extending the OCI of the oil. Yes, improved filtration does improve engine life but it's not by a huge factor (despite the ad hype you see... you have to look close at the test data because it often measures wear of highly filtered oil against a crankcase full of highly contaminated oil, not the type of oil that you would normally let remain in your engine).
3) Improve the oil. A stronger additive package lasts longer in any operating condition. The base oil (i.e. synthetic vs conventional) is less important from this standpoint because it has little effect on how long the additives can do their jobs. A slippery syn base oil can reduce wear, and that helps, but the difference in wear between a syn and good conventional is not huge.
If you have to pick one thing to improve, my advice is to pick the air filter (and related crankcase breathers). Again, that is the source of 90 percent of engine contamination. Make sure the filter housing seals well to the intake. Make sure the filter seals in the housing well (use filter grease for sealing). Duct the intake hose to the cleanest source of air (generally the stock location). Make sure your CDR drain seals well in the valley pan or valve cover and the o-ring into the intake is good. Make sure there is a good seal on your oil cap. If you have a turbo, make sure your many intake clamps are tight (sues some sealer on the hoses). If you have a road draft tube, go back to a CDR or some other sealed breather. There are better and worse air filters out there but that's a LONG discussion. In general, if you by the premium level filter (most brands have the cheap price point "bronze" filter then "silver" or "gold" you get the idea), it will have better, more efficient media. I have seen testing that indicates this. Avoid oiled cotton gauze, foam (unless backed up by other better media) or oil bath filter media because they can be very inefficient.
You can improve oil filtration effectively and economically by using the Powerstroke oil filter, which is more efficient (19 micron nominal vs 28 nominal generally). The Powerstroke spec'ed a more efficient filter because of HUEI and that increase translates to all the brands that make filters for the application. On top of that, the PSD filter has about twice the media, so you can run it lots longer. There are high dollar synthetic oil filter out there that cost about twice as much as a regular filter. They are very efficient, long lasting and good but the numbers don't always crunch unless you run an extended OCI.
Finally, I've given you a lot of generalities above but if you want to go really long on the OCI, the only way to judge how long YOUR oil can go in YOUR individual conditions is via oil analysis. If you want to play this game bigtime, you gotta learn the rules. To be honest, until you do your testing, it will be MORE expensive to chart your way than just to dump the oil arbitrarily and be done with it. IMO you can safely extend to two or three years 6-8,000 miles pretty easily with minimal testing but there are still a LOT of variables. I suggest a first step is to get an oil sample (google Blackstone Labs) according to solid sampling guidelines when you do your next OCI. Don't look at it as a guide to engine condition (you can't get that from one sample), just oil health. Pay extra for the TBN test. That test tells you how much of the additive package is left. If your test is like most and you are doing short (4,000 miles or less) OCIs, you will probably find you were dumping oil with a LOT of life left.
Since winter is here, another tip. Plugging the truck in is conducive to longer oil life (and better mpg) because it gets the oil warmed up faster. Our engines have an advantage in that the oil cooler is also an oil warmer so warmer water in the cooling system get the oil warmer sooner. Vs some other engines I have seen or owned, the oil temp on my IDI reaches a warmed up state much faster. And that's a GOOD THING!
