3000 mile oil change myth...

[LUVMYRT]

I saw this on Yahoo today and thought everyone would like to take a look see.


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.

[formerice]

Good article. I'm still gonna change mine at 5,000 , it's worked for 136,000 miles, my car still uses no oil and I removed the catch can after 10,000 miles of use it had 2 drops. The best thing to do would be to send a sample off to Blackstone labs, then you'll have a better handle.

[MattRobertson]

My daily car has a 13000 mile service interval. Which is like two and a half months with the commute I have.

The mag still gets changed at 3k miles, or after a track day, whichever comes first.

[2005rtmag]

Everything I've read on synthetic said that it could be used for up to 15k especially if you change the filter and add a qt to makeup occasionally.

Plus, I've also read that in Europe, 10k oil change intervals are normal.

I switched to synthetic at 21K and change at 6k miles since then. Since mine is a 2005 model with the 7/70 drivetrain warranty, I don't want to give the dealer an excuse not to honor the warranty if it is needed. I keep my oil and filter receipts with a log book and change the oil myself.

I use Mobil 1. I've also read in several places that Amsoil oil viscosity gets higher with miles and may not be acceptable for close tolerance engines.

[desquirrel]

Oil formulations are a compromise like everything else. There are many people that buy "boutique" oils like Amsoil or Royal Purple because of internet hype.They somehow figure 5 guys in a garage figured out something that has eluded Mobil and the rest. It's all BS. Amsoil on extended use has shown dramatic swings in viscosity which Mobil finds objectionable. This information is not new. CR tests found much the same thing in the 70s. The ONLY thing you get from boutique oils is a lighter wallet, which is the exact same thing you'll get if you use syn over dino and change at 3K.

It does not matter how many studies are done. They will still line up to buy "Super Royal Scarlet with teflon coated atomic particles" because they read it on the Internet.

[JarZ]

I have 600 miles since the last oil change where I went to Mobil 1 synthetic. I'll let it go to 5k before changing it but before I have always done the 3k. As long as the oil is still good as you found out, there's no reason to change - it's correct about Europe - 10k is definitely common for an oil change interval and I wonder about that too. I also still have the powertrain warranty but up to 80k so I'll keep it at around 5k from now on with the synthetic

[LUVMYRT]

It does not matter how many studies are done. They will still line up to buy "Super Royal Scarlet with teflon coated atomic particles" because they read it on the Internet.

LOL!!!

[MagnumFierce]

WHOA! Teflon coated?? I'm IN!!
Especially if a celebrity who has never driven a car, endorses it.

BWAAAHAHAHA

Actually it's funny, the service guide that came with my `05 MRT says
either 3k or 6k between changes. And the language is funky and unclear
enough to sway you towards the 3k. And we are supposed to use that
sort-of-synthetic-oil-cocktail for the Hemis.

Unless I see dark, or dirt on the dipstick, or any smell, I'm going every 6k.

Probably switch over to full synth at 50-60k or so.

[stitchmonkey]

So this is where all the oils going!

[viper3ez]

7 quarts every 3 thousand miles

21000 miles divided by 3,000miles equal to

7 x 7.

so i use 49 wuarts of oil yearly.

say no th 3,000mile oil change

[Super T]

I just went 22 months, about 15,000 miles, in my Cutlass... oil came out looking like it's only been in there for 3,000 miles. And that wasn't even synthetic.

[HCCAFan]

So what's the interval? It used to be 3 months, or 3000 miles. If it's not 3000 miles, how many months is oil good for. My maggie doesn't usually see even 3000 miles in 3 months.

[stevesrt8]

we run a fleet of 6.0 gas Savana's on synth, their oil life monitor calls for changes anywhere from 4500 miles to 15,000. Depends on the duty cycle.

My Silverado (5.3 gas) usually wants one at about 12-14000.

My SRT8 gets one every 3000 so they got no excuses!

I run Amsoil in everything. I have one engine/trans combo with over 300000 miles on it, no smoke, no drip, no slip. Running an EXTREME duty cycle. So say what you want, the **** works good! When I see the big rigs running their oil for a year or more with a bypass filtration setup I know it's no joke.

Most everyone has figured out that it was the oil change places that came out with the whole 3K "myth". Duh, don't they sell oil?

And the last point is if you don't analyze, you're just guessing. Oil analysis is cheap, and after you develop a baseline you don't need to do it every time.

[prican_2000]

I used the Mobil 1 Clean 5k and I change it every 5k miles- No problems Thus Far.
I think I used to put 3k miles on my car every month, so I pushed it to the 5K. Now that I drive the car less I still keep it at 5K.

You also have to take into consideration the wear and tear that stop and go traffic puts on our engines- I rather be safe and spend the ~30 on the oil changes.

[CombatMedic67]

Most everyone has figured out that it was the oil change places that came out with the whole 3K "myth". Duh, don't they sell oil?

Hmmm...you would think that everybody has figured that out...but it's not true. I know my mother back home wouldn't have inclination to think her change oil sticker that they slap right in your field of view is lying to her. They got people wrapped around their proverbial finger. It's absurd!