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From: Vic Smith on 31 Mar 2010 11:17 On Wed, 31 Mar 2010 09:47:17 -0500, jim <"sjedgingN0Sp"@m(a)mwt,net> wrote: > > >So how does that explain your obsession with what other folks do? Some people want to feel superior, or it could be they want reinforcement of their own beliefs, because they are not sure of those beliefs. But maybe when you see the same people saying they don't have to change their oil until 10000 miles go by, and they don't have to wax their car, it's a simple case of trying to justify their laziness and/or penuriousness. Like, "What, you bathe more than once a month? That's a crazy waste of precious water and heating fuel. Does no good and costs money." Could be something like that, but hard to tell without doing a psychological analysis. Personally, I don't care how often people bathe, so long as they don't stink up the place. Don't care at all how often they change their oil. --Vic.
From: SMS on 31 Mar 2010 11:34 On 31/03/10 6:12 AM, jim wrote: > The question is why are there so many zealots on the internet that feel > it is their mission in life to convince other motorists that it is good > to be driving around with black oil in their engines? I think the source of your confusion has been identified. You mistakenly believe that the color of the oil is indicative of its lubricity and its level of contaminants. Dark oil does not indicate the need for an oil change. The way modern detergent motor oil works is that minute particles of soot are suspended in the oil. These minute particles pose no danger to your engine, but they cause the oil to darken. A non-detergent oil would stay clearer than a detergent oil because all the soot would be left on the internal engine parts and would create sludge. If you never changed your oil, eventually the oil would no longer be able to suspend any more particles in the oil and sludge would form. Fortunately, by following the manufacturer's recommended oil change interval, you are changing your oil long before the oil has become saturated. Remember, a good oil should get dirty as it does it's work cleaning out the engine. The dispersant should stop all the gunk from depositing in the oil pan. The only real way to determine whether oil is truly in need of changing is to have an oil analysis performed. Since most people don't want to bother with this, it's acceptable to err heavily on the safe side and simply follow the manufacturer's recommended change interval for severe service. There is no benefit in changing the oil earlier than this. You're not increasing your engine's life by changing your oil every 2000 or 3000 miles versus 5000 miles.
From: jim on 31 Mar 2010 12:30 SMS wrote: > > On 31/03/10 6:12 AM, jim wrote: > > > The question is why are there so many zealots on the internet that feel > > it is their mission in life to convince other motorists that it is good > > to be driving around with black oil in their engines? > > I think the source of your confusion has been identified. You mistakenly > believe that the color of the oil is indicative of its lubricity and its > level of contaminants. No i don't believe anything of the sort. The color of the oil indicates the color of the oil. The question I ask is why do you care if someone else prefers not to have a certain color oil? > > Dark oil does not indicate the need for an oil change. The way modern > detergent motor oil works is that minute particles of soot are suspended > in the oil. These minute particles pose no danger to your engine, but > they cause the oil to darken. Actually that is not exactly true. There is a remote possibility that those particles could become harmful to the engine. For instance if you are tooling down the interstate and you head gasket lets loose and suddenly it dumps a bunch antifreeze into your oil. That will very quickly use up all the dispersant/detergent additives in the oil. That means the particles that were happily being held in suspension doing no harm will start to rather quickly precipitate and agglomerates into larger particles and that can cause harm. Fresh clean oil can absorb more antifreeze before engine damage occurrs than old black oil can. Saying extended oil changes are safe is based on the assumption that the engine is always going to be functioning properly. Keeping the oil cleaner than it needs to be can be insurance against certain types of malfunctions such as when excess fuel, antifreeze or dirt get dumped into the oil unexpectedly. Those may not be likely occurrences, but they do happen. Also, the older dirt laden oil is much less able to maintain it's viscosity and shear properties if the engine overheats excessively. And in this day and age excessively overheating engines is probably the number one cause of lubrication failures. Blow a radiator hose and the temps inside an engine can very quickly exceed 250C. > A non-detergent oil would stay clearer > than a detergent oil because all the soot would be left on the internal > engine parts and would create sludge. If you never changed your oil, > eventually the oil would no longer be able to suspend any more particles > in the oil and sludge would form. If someone changes their oil often enough so that it doesn't get black they never have to worry about whether they have reached the point where the additives can no longer protect the engine from the dirt. For instance if someone has a half a dozen cars, maybe its just a lot simpler and safer to change the oil when it starts to get very dark rather than keeping detailed records for so many vehicles. > Fortunately, by following the > manufacturer's recommended oil change interval, you are changing your > oil long before the oil has become saturated. Remember, a good oil > should get dirty as it does it's work cleaning out the engine. The > dispersant should stop all the gunk from depositing in the oil pan. > > The only real way to determine whether oil is truly in need of changing > is to have an oil analysis performed. But who cares if you happen to change the oil before you absolutely need to? I mean you probably don't wait to eat until you reach the point where it adversely affects health. You probably pea a lot more often than you really have to. Many people don't wait till April 15 to file their taxes. Doing things before it is absolutely positively necessary is pretty common human behavior. The question is why is this one particular behavior the one that gets so many people agitated? -jim >Since most people don't want to > bother with this, it's acceptable to err heavily on the safe side and > simply follow the manufacturer's recommended change interval for severe > service. There is no benefit in changing the oil earlier than this. > You're not increasing your engine's life by changing your oil every 2000 > or 3000 miles versus 5000 miles.
From: Jeff Strickland on 31 Mar 2010 12:41 "jim" <"sjedgingN0Sp"@m(a)mwt,net> wrote in message news:_6Odnew3LYMu5S7WnZ2dnUVZ_rKdnZ2d(a)bright.net... > > > SMS wrote: >> >> On 31/03/10 6:12 AM, jim wrote: >> >> > The question is why are there so many zealots on the internet >> > that feel >> > it is their mission in life to convince other motorists that it is good >> > to be driving around with black oil in their engines? >> >> I think the source of your confusion has been identified. You mistakenly >> believe that the color of the oil is indicative of its lubricity and its >> level of contaminants. > > No i don't believe anything of the sort. The color of the oil indicates > the color of the oil. The question I ask is why do you care if someone > else prefers not to have a certain color oil? > >> >> Dark oil does not indicate the need for an oil change. The way modern >> detergent motor oil works is that minute particles of soot are suspended >> in the oil. These minute particles pose no danger to your engine, but >> they cause the oil to darken. > > Actually that is not exactly true. There is a remote possibility that > those particles could become harmful to the engine. For instance if you > are tooling down the interstate and you head gasket lets loose and > suddenly it dumps a bunch antifreeze into your oil. That will very > quickly use up all the dispersant/detergent additives in the oil. That > means the particles that were happily being held in suspension doing no > harm will start to rather quickly precipitate and agglomerates into > larger particles and that can cause harm. Fresh clean oil can absorb > more antifreeze before engine damage occurrs than old black oil can. > Saying extended oil changes are safe is based on the assumption that > the engine is always going to be functioning properly. Keeping the oil > cleaner than it needs to be can be insurance against certain types of > malfunctions such as when excess fuel, antifreeze or dirt get dumped > into the oil unexpectedly. Those may not be likely occurrences, but they > do happen. Also, the older dirt laden oil is much less able to maintain > it's viscosity and shear properties if the engine overheats excessively. > And in this day and age excessively overheating engines is probably the > number one cause of lubrication failures. Blow a radiator hose and the > temps inside an engine can very quickly exceed 250C. > > > Sorry for jumping in in the middle here, but it appears to me that you're suggesting that the bad effects of a blown head gasket can be mitigated by clean oil. That's a huge falacy. If the head gasket lets go, it won't matter if the oil was changed 10 minutes or 10 months ago. The contamination of the coolant into the oil is the least of the problem when the head gasket goes.
From: jim on 31 Mar 2010 14:15
Jeff Strickland wrote: > > Sorry for jumping in in the middle here, but it appears to me that you're > suggesting that the bad effects of a blown head gasket can be mitigated by > clean oil. That's a huge falacy. Well I'm sorry but the SAE doesn't share your opinion. There have been a number of studies on levels of antifreeze contamination on oil and its effects. > > If the head gasket lets go, it won't matter if the oil was changed 10 > minutes or 10 months ago. The contamination of the coolant into the oil is > the least of the problem when the head gasket goes. No not really, in terms of immediate consequences contamination of the oil can be the only real concern. A small amount of antifreeze lost from the cooling system won't impact on the engine temp and if the coolant leak is from the water jacket into crankcase then the only short term consequence at all is the contamination of the oil. That is not to say you can't create a scenario of head gasket failure where it doesn't matter how old the oil is. Even if it doesn't matter most of the time, that misses the point. The point is that no matter how improbable it may be it is possible to have just the right kind of leak with just the right amount of leakage that whether the oil is old or fresh can make a difference. So anyone who tells you there is no possibility that the fine particles suspended in the oil, that accumulate with miles, is going to ever cause harm is simply not being accurate. The best you can say is that it is unlikely they will ever cause harm. -jim |