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I'm a new car owner for the first time this year, and with that seems to come some different experiences as compared to having a car with 80,000+ pre-owned miles on it. One of these has been the arrival of my first "Oil Change Needed" alert.

The car is a 2012 Dodge Avenger. The manual suggests an oil change interval of around 8,000 miles. So, it was much to my surprise when the computer indicated an oil change needed after only 3,500 miles. I checked in with the dealership to see if this was a malfunction. They told me some things I've also confirmed in the aforementioned related threads:

  • The Oil Change indicator is triggered by things like oil viscosity and other qualities - not just a mileage counter.
  • These things can be affected by driving habits - highway miles generally get more life out of the oil than city miles.

Despite this I was still feeling a bit confused as to why, when probably 80% or more of my driving is on the highway, the car was prompting me for an oil change at less than half the normal interval stated in the manual. Then, the dealership mechanic told me something to the effects of this:

It's normal for the first oil change to be sooner, because the engine still has to flush out some metal shavings and other contaminants left behind from the manufacturing process.

To me, it would seem rather ridiculous that a manufacturer would allow such contaminants to exist in what the common consumer is expecting to be a pristine new engine. However, this is also the only explanation that I can think of which seems probable if we want to exclude certain other possibilities like sensor malfunction or bad business practices.

So, am I being properly informed or is the dealership feeding me a bit of a line?

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I very much doubt there's any loose bits or "metal shavings" rattling round in your new engine as it rolls off the assembly line, but a new engine experiences more wear as the parts "mate" with eachother. These wear particles end up in the oil, so a quick first change is a good idea. –  mac Nov 29 '12 at 16:39
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2 Answers

The first one is usually a much shorter interval, yes. This allows for bedding in, possibly flushing contaminants (I'd be upset if I had metal shavings in my engine when I got it) and allowing minor tolerance differences to be smoothed.

Often a different oil type is used for that first period to assist with this process.

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From my understanding of the way the GM "oilminder" works the computer monitors various engine conditions and mileage and possibly time. In my case I short cycle the engine (start it up and shut it off before it reaches normal temperature) quite often as I have a short commute. This allows condensation to potentially accumulate in the crankcase. If the oil reached normal temperature this would evaporate. So the computer is tracking shortcycles, load ,rpm, oil pressure etc. Then the software decides when you should change the oil. I know the system works because in the winter when the engine never warms up it can signal a change in as little as 2000 miles. In the summer it may never send the signal as I never go over 5000 miles between changes. As far as what set yours off early it may have been the assembly lube that was used when the motor was assembled. It is much thicker than oil and get washed off the rotating parts by the oil as it circulates. This may have partially clogged the filter resulting in change signal. It is also possible that either the vehicle was started frequently at the dealer so the oil had hours of use with little miles or that it was calculated based on how long since the first engine start. I would monitor the time intervals for a few changes before being concerned. Just remember the computer is also monitoring how long you drove with "change oil soon" light on. Ignoring it could result in some headaches if you need to make a claim under warranty for engine repairs.

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