And I stand by that comment. The only way I'd run 6k miles on a conventional motor oil change would be under the same conditions, 100% freeway in a short period of time.

 

Try getting warranty on your engine if you are going 12k miles. You have to get an oil change minimum 10k miles, that is the schedule. If you change your conventional oil 3000 miles or 3 months you can bet you will have an engine that lasts as long as an engine with synthetic. It's the people who really go the 6K miles before oil changes everytime . Can the dealer find out if the light came on and it was reset and if the oil is old and dirty why doesn't the light come back on? Useless light, could be better used on something else.

 

Ever wonder why an car company that makes money on oil changes have short oil change intervals, even with synthetic? Take for instance, when the car company is picking up the tab, like my Wife's new BMW X5 which comes with 3 year maintenance covered, they recommend 15K miles or one year for an oil change.

IMO, anyone that changes their oil every 3K is not only throwing their money away, but is not also considering the environmental impact.

I'm going to look for an article I read that their tests suggested that synthetic motor oil doesn't fully reach it's peak protective cycle until after 2K miles of break in. Under this concept, frequent oil changes can ironically be detrimental to the longevity of your motor.

 

About 25 years ago, Consumer Reports conducted an exhaustive piece of research comparing conventional, synthetic-blends and straight synthetic oils. They used New York taxi cab fleets as their test vehicles, racking up 10's of thousands of miles in a relatively short period of time. The study involved most major brands of oil (including Mobil 1) and oil performance was based on chemical analysis for oxidation and heavy metal content. Some engines were randomly picked and disassembled to measure bearing tolerances. The report concluded:

1) There was no difference in the performance of brands with the same API service and viscosity rating. Perforance of non-API rated oils was not predictable.

2) There was no advantage in using synthetic oil over conventional where oil changes were fairly frequent, which was 3,000 to 5,000 miles in the study.

3) Synthetics possessed superior oxidation characteristics (they don't burn as easily) which permited extended use to 10,000 miles between changes. Blends performed in the middle.

4) The report recommended more frequent filter changes where synthetic oils were being used for extended periods. The best documented example I have seen of someone using synthetics this way can be found at http://www.hyundai-forums.com/t48882...thetic-oil.htm.

Oils have gotten a lot better, but it seems the basics of this report still apply. The study also looked at novelty oils (aka, teflon imprenated oils, etc), disproving any benefit from using such products. I remember the report because I was using an oil called ARCO Graphite at the time. Contained finely ground graphite suspended in the oil and poured coal black from bottle. I was using the oil because it seemed to help with starting at sub-zero temperatures. The product worked OK until the oil started to experience viscosity break down and the graphite had a tendency to drop out of suspension, causing nasty things to happen. Yes, I quit using the product after reading the report.

I agree with the comments about protecting warrenty protection.

 

Not only have the oils gotten better, but so have the engine production methods and tolerances. If you do your homework on the history of synthetic oils you will find that improvements have been made by leaps and bounds when you look at how synthetic oils of yesteryear protected engines of yesteryear and compare them to their protection of engines today. Taking a 25 year old study and applying it to today is apples and oranges.

 

Secret Agent Man is right. Synthetic oils have come a long way and come in many flavors. You can buy an extended synthetic oil that will allow you to go 12000 miles before it even starts to breaks down. My wife's Mercedes does 10000 mile OC. That 10000 mile OC is from the dealership. The oil used is Mobil 1 0w 40 European formula. I do 5000 mile oc on my 5.7 using Valvoline synthetic or Quaker State synthetic. It's only 18.50 for 5 qts of the QS synthetic and I think 5000 is a safe number because of some extended idiling. My OLR comes on at about the 6000 mile mark.

 

I think you are looking at Kilometers. The spec in the manual is 6000 miles

As for the synthetics I'll continue to pass. $20 (with coupon) at the dealership for the regular stuff every 3-5K miles is just fine with me. Gives them a chance to perform the next stack of RRTs that much sooner

 

We here are talking about Mopar. not mercedes or BMW.
Dodge recommends on the new eagle hemi 6,000 miles per oil change synthetic or not. (you can go further for your own sake, but i wouldnt recommend it.)
Jeep KJ (liberty) recommends 6,250 miles on thier 2.8 turbo diesel motor, with european blend oil. (used in gas and diesel engines... no difference in euro formula)
Cummins recommends every 7,500 miles for my truck. If i run a good synthetic diesel motor oil, you wont ever catch me running 15,000 miles on an oil change.
I keep with the schedules, because its what mopar recommends and that is what will make my vehicle last.

 

The manual for my 21 year old truck recommends changing the oil every 7k for light duty, and 5k for severe duty. And thats with conventional oil.

On another note, i know a guy with a late 80s ford with a 300 i6. He never changed the oil, and just added a quart every few months. He scrapped it at ~250k, a year or two ago, because the truck rotted out from underneath him.

 

ive been going with mobil 1 syn since my first oil change and i usually go about every 6000 miles or so... ive heard many respected forum members on this site and ford sites who swear that 10,000 mile synthetic oil changes are not a prob as long as you switch out the filter.

but after my latest trip to indiana from LA, i went to my local dealer to do a change because (as expected because it was coming up due) my oil light came on.. so i went to the dealer and they stuck regular oil in because i forgot to mention i use mobil 1...

and i dont know if its because the truck hasn't adapted to the elevation, humidity or heat... but my truck sure doesn't run as quick as it did before i got the oil change.