According to a recent study by the California Integrated Waste Management Board, 73 percent of California drivers change their oil more frequently than required. This same scenario no doubt repeats itself across the country. Besides wasting money, this translates into unnecessary consumption of $100-a-barrel oil, much of it imported.
Using 2005 data, the Board estimates that Californians alone generate about 153.5 million gallons of waste oil annually, of which only about 60 percent is recycled. Used motor oil poses the greatest environmental risk of all automotive fluids because it is insoluble, persistent, and contains heavy metal and toxic chemicals. One gallon of used oil can foul the taste of one million gallons of water.
It’s been a misconception for years that engine oil should be changed every 3000 miles, even though most auto manufacturers now recommend oil changes at 5,000, 7,000, or even 10,000 mile intervals under normal driving conditions.
Greatly improved oils, including synthetic oils, coupled with better engines mean longer spans between oil changes without harming an engine. The 3000 mile interval is a carryover from days when engines used single-grade, non-detergent oils.
For several years, automakers like General Motors, BMW, and Mercedes-Benz have installed computerized systems that alert drivers via an instrument panel light when it’s time to change oil. As an example, the General Motor Oil Life System (GMOLS) analyzes the engine temperature, rpms, vehicle speeds, and other driving conditions to calculate the rate of engine oil degradation. Then, software calculates when the oil needs to be changed. Other systems work similarly.
Because of the many external conditions and parameters that have to be taken into account, calculating the precise maximum service interval using mathematical models alone is difficult. Now, Daimler AG has developed a more direct and precise way to monitor oil quality directly on board a vehicle.
Daimler uses a special sensor integrated into the oil circuit to monitor engine oil directly. Oil doesn’t wear out, but rather dirt and impurities cause oil to lose its ability to lubricate properly, dictating the need for a change. Daimler uses the oil’s “permittivity,” that is, the ability to polarize in response to the electric field. If the engine oil is contaminated by water or soot particles, it polarizes to a greater extent and its permittivity increases.
To evaluate the quality of the oil, permittivity is measured by applying an AC potential between the interior and exterior pipes of an oil-filled sensor to determine how well the oil transmits the applied electric field.
Because not all impurities can be measured with sufficient precision via the electric field method, Daimler also measures the oil’s viscosity to detect any fuel that may have seeped into the oil. Daimler researchers measure viscosity while the vehicle is in motion by observing the oil's side-to-side motion in the oil sump. The slower the oil moves, the higher its viscosity. This movement is registered by a sensor and the viscosity is calculated on this basis.
A single sensor, along with the information already monitored by on-board computers, is sufficient to determine the various parameters of the engine oil. Daimler will likely use the technology first on its commercial vehicles. Here, large oil reservoirs mean larger quantities of oil can be saved. Plus, a predicted 25 percent increase between service intervals and reduced downtime will be of interest to fleets, and thus justify the added cost of installation.
don't you think that the manufactuers want you to change oil as infrequently as possible so that you can replace your engine at 150,000 miles instead of 250,000?
With the oil life monitors, I definitely think there's some of that going on.
I have noticed that the price of a quart of oil has SKYROCKETED over the last 6 months.
I didn't notice it until today since I usually get my oil changed at Firestone (10W30 synthetic Kendall)
I just changed my engine oil (and filters) in two vehicles tonight. My 1997 Sebring (2.5L) and my 2002 Ford Mustang (3.8L). On BOTH these vehicles, I have LESS than 3,000 miles since the last oil change (BTW, I was very surprised that both were a little above 2,000 miles since the last change, I expected even less).
The oil did NOT look all that clean. The last time I changed oil in these vehicles was in Feb of 2007. So the engine oil has been in these vehicles for one and a half years.
I usually change the oil in these two vehicles once per year because they don't get much use. I waited a bit longer this year, I guess because I had other things to do while here that were more interesting than changing oil.
BTW, does anybody here have a hangup about mixing brands of oils in an oil change? My Sebring needed 4.5 qts of 10W30 engine oil. I found exactly 4.5 quarts of 10W30 oil in the garage. 2.5 quarts of Pennzoil, one quart of Castro and one quart of Chevron oil and used them all in this oil change.
I had plenty of 5W20 (all Pennzoil) oil for the Ford and many filters for both.
I had a choice to go out and buy more oil for the Sebring or just mix the brands. Since I had everything to complete both jobs, I decided to get the job done by using different brands of oil. I've never done that before, I normally even stick with the same brand from one oil change to the next.
-Don- (Reno)
It's not a thing I've ever done, but I don't really see any problem with it. If you download spec sheets from oil manufacturers' websites you'll see that in most cases they specify that their oil can be mixed with other oils. Miscibility may even be part of the SAE & other specs for oils - it certainly is for brake fluids.Originally Posted by DonTom
Could very well be!
I still stick with every 4 four months or 3,000 miles for my truck - whichever comes first.
I may be overcautious and spending a little more on oil/filters than I need to - but doing it this way absolutely isn't hurting anything while pushing the envelope just might!
"BTW, does anybody here have a hangup about mixing brands of oils in an oil change?"
No issue there - provided the oils used all meet the minimum specs listed by the automaker.
"but doing it this way absolutely isn't hurting anything while pushing the envelope just might! "
Don't be so sure. I've heard that the additives in oil when fresh wear down some parts faster than oil with a couple of thousand miles on it. IOW, it might be possible to change engine oil a little too often.
If there's any truth to this, I am not sure.
-Don-
That sounds fishy.
New cars with brand-new engines come with fresh oil in them. And even though "break in" is not what it used to be, it's still a time when an engine is susceptible to premature/excessive wear. If the above were true, I would expect the car companies to either fill new car engines with slightly used oil - or "special" oil with fewer additives, etc.
My Honda, when bought, came filled with a low additive 'running in' oil. I was told, by my dealer, that it should stay in the bike up to the first (600 mile) service at which point it would be changed for a normal fully synthetic oil. The initial oil is used as part of the running in programme as it allows the moving parts to bed in against each other - using a full additive oil from the beginning would inhibit this bedding in process.
Ken.
That sounds fishy.
New cars with brand-new engines come with fresh oil in them. And even though "break in" is not what it used to be, it's still a time when an engine is susceptible to premature/excessive wear. If the above were true, I would expect the car companies to either fill new car engines with slightly used oil - or "special" oil with fewer additives, etc.
Die dulci fruimini!
Ken.
Wolds Bikers, Lincolnshire, England.
I certainly doubt it. All additives are, in addition to their stated role, included because they tend to reduce wear.
"I certainly doubt it. All additives are, in addition to their stated role, included because they tend to reduce wear."
I hear some additives are to clean and that's the problem. Remember the old term "detergent" oils? They work a little too well for the first few miles. Another theory is that in every oil change you run for a few seconds without oil in some parts of the engine and this increases wear when done too often.
-Don-
"And even though "break in" is not what it used to be, it's still a time when an engine is susceptible to premature/excessive wear. If the above were true, I would expect the car companies to either fill new car engines with slightly used oil - or "special" oil with fewer additives, etc."
I don't agree. A good break-in requires wear, but a clean even wear.
You don't want to increase the time it takes for a good break-in.
-Don-
I agree with that; but its equally true that the OEMs fill their brand-new engines with "regular" oil, which is what they leave the factory with (unless I am misinformed).
The practice of using non-detergent break-in oil - at the OEM level at least - is pretty much a thing of the past.
Not likely. On an old, very dirty engine running high detergent oil can be a big mistake, but in an engine that's reasonably clean to start with no problem.
Upon any shutdown oil remains throughout the engine, and is the lubricant for the brief time it takes pressurized oil to begin flowing. That is true for an oil change just as it is for routine parking. You might say that frequent starting/stopping increases wear, but I'd want to see some lab tests on that.
"That is true for an oil change just as it is for routine parking."
Haven't you ever looked at your oil pressure gauge right when you start after doing an oil and filter change? It doesn't compare to a cold start after being parked overnight.
-Don-
Oil pressure gauge? - it's been quite some time since I owned a car with such a gadget - "idiot" lights are all the rage these days.
Anyway, given the relative infrequency of oil changes - every 3k miles would be 5/a year for 15K miles, I suspect that any additional wear would be negligible.
""idiot" lights are all the rage these days."
That will do. After your next oil & filter change, start the engine and see how long it takes for your oil lamp to go out. Compare that to being parked overnight.
How long do you think the engine would last if you changed your oil every five minutes and restarted it after each change? ;D
-Don-
Since oils have changed a lot through the years, I still remember when a "non detergent" oil was the norm for all break ins. It was left in for about 1500 miles and then 'dumped'. At that time, a dealer would, in some cases, cut open the oil filter, if equipped, to check as to what types of metal were to be found.That would tell the mechanic and dealer if any problems were on the horizon. Of course, the engines of yesteryear were not as sophisticated as those being built today. And by changing the oil every 3000 miles was the norm, most engines did not have a filter. And detergents were not used like they are today. I think the most confusing part about oils, are the many types that are out there. There was a time when mixing oils could be a problem because of the chemical make up or additives in it. Each company would void any oil related problem if they found out that you used a brand other than what was put in your vehicle. And each car manufacture would also void your warranty if you used anything other than what the manufacture said. Example, stamped on a lot of fill caps were the Brand, Viscosity, and alternatives that could be used. And, oh yes, don't forget that 45 miles per hour was also the norm for those 1500 miles. I'm glad that engines are built today with little or no break-in period. Engines are not built with as close clearances as years passed. This does allow for quicker breakins as well as being able to maintain highway speeds. Can you imagine driving 45 miles per hour for 1500 miles today? You'd be "K-Womped by a Peterbuilt hualin' a Freightliner with a Big Dog on its heels. I have been told that you can mix most oils as long as the specks are the same. Now, when it comes to synthetics, I've also been told that you can mix them with petroleum based oils as well. I'm not sold on that yet, and I'm not ready to donate my engine to science. I have to agree that oils changes come way to soon. I can understand that in hard usage. I feel that with the new technology and R & D being used, that oils are as good if not better than what they were thirty, forty years ago. Isn't that when manufactures started telling us that we could go 5000 miles between oil changes in the first place? And don't forget our 50,000 lube jobs. I think that if a person paid attention to the API Service on the can, there should be no problems. Only if they pay attention to the viscosity of the oil. That can and will cause more damage on start up than any thing I know. And how long can an engine run with out oil? Quite a while, go to just about any car show that has an engine blowing event. I've seen engines go for a hell of a long time without oil or water, only to be brought back the following year to try to finish the job. Does an old Ford six bring back memories? ;D
Probably long time!
As I understand it, a sufficient film of oil remains on all friction surfaces to provide lubrication upon start-up, until pressure is built.
Now, with a newly built engine, initial start is more risky because there is no oil on the cylinder walls, bearings, etc. This is why it's important to coat such surfaces with a break-in lube....
Posting Permissions
Reply With Quote