I took my "new to me" 2004 Audi A6 3.0 to the dealer for an oil change. when I made the appointment I was under the impression that they would be using synthetic, but when I got the car back I later noticed on the invoice that they used regular. The car has always had synthetic in it, but they tell me that the 2004 A6 had some engines that took regular oil, and according to my VIN mine was one of them. I insisted that they change the oil to synthetic, but after they did that I noticed a couple of days later on the invoice that they didn't change the filter, and that they overfilled the oil. So now they have a mix of regular and synthetic in my engine, and are going to change it again. My question after all this writing is, will any of this cause any issues with my Audi, any problems with this at all? Can the different oils be mixed like that without issues? I probably have about 200 miles on the engine during all of this debacle. Any advice is appreciated.
Thanks for reading!

 

As for the stupid dealer consideration, I would curse them and ask them to fix it right. As for whether it will damage your car, no, not really. Just have them drain, change filter, and refill with synthetic. That is what you paid for.

 

Thanks hx, that was what I was thinking, but wanted to confirm. A couple of people have told me you can't mix the two oils...it's kind of like oil and water, but they are both derived from petroleum so I don't think hats the case.

 

You can mix the two oils with no problem. The dealer should be using a synthetic oil recommended by Audi, such as European Formula Mobil 1 0W-40. But I would not lose sleep over their miss-step. Visit the site "bobistheoilguy.com" if you want to learn more about this subject.

 

thanks for the input...much appreciated. I'll check out the site you recommended.

 

Not to defend the dealer but, the '04 3.0L used conventional oil originally so if you didn't specify synthetic.......................They should have asked which you wanted though.

As mentioned, they mix no problem. All semi-synthetic oil is synthetic mixed with conventional. It's about 4 parts conventional to one part synthetic and I've never understood the reasoning. I mean, either use conventional or full synthetic. JMO

 

Thanks for the input, I appreciate the responses I'm getting here. It appears I have nothing to worry about. I'm not sure I see the advantage of semi-synthetic either. My understanding is that when mixed, you really don't get the benefits of the synthetic.
My frustration with the dealer was that I didn't get what I wanted, but they took care of it, and gave me my next oil change at no charge.