Is there really such a thing as Break in Oil ?
 

I was reading in these pages about break in oil.
Personally I think it is regular oil used in a new engine.
Some people talk like there is a special oil with "break in properties".
Makes me think there are abrasives in it to smooth out the rough edges, help the rings grind themselves into the cyl wall etc.
Whenever I hear somebody talking about "its got the break in oil in it".
I ask "whats break in oil". Still waiting for a straight answer.

Wow I haven't heard that term in years. Break-in oil used to mean the manufacturer's recommended oil for the first 500 - 2,000 miles on a newly minted motor. It's not an issue with new cars since manufacturing and machining technology has gotten better and better to the point that it's just not necessary. This is not to be confused with assembly lube used when rebuilding a motor.

If break-in oil still exists, I believe it is made with higher amounts of ZDDP ("zinc") than you find in regular motor oil. This additive is an antiscuff agent that bonds to metal and heals the metal any time there is metal-to-metal contact. I don't think manufacturers use it any more.

Our resident lubrication expert where I work recommends dumping the initial oil charge as soon as the new car is home to get rid of the manufacturing grit found in a new engine. A bit extreme, but there is some truth to his thinking.

My '95 VW Jetta GLX with the VR6 engine had non detergent pure mineral oil for break in oil.

When I purchased my Jetta in 1997 ( new ), I noticed the oil had a very green ! look to it.
The dealer was quite adament about leaving it in there for the duration specified by VW. ;)

On my '96 Jetta I foolishly had the first oil change done early....I thought I was being "good" to the car. What I ended up with is a motor that burned oil to the tune of one quart per 800 miles.

mineral oil
 

I was working at an airport as a aircraft fueler and we would help the mechanics preflight aircraft that had a rebuilt engine installed. For the first 20 hours (filter changes every 5) they were instructed to use aeroshell 80 or 100 (40 or 50 weight) non detergent mineral oil. This oil is designed to encourage wear in all the tight spots in the engine and to get the rings to seat. The high detergent and synthetic oils do not allow the engine to wear in properly, as mentioned with the oil burning WV. If parts are machined to very close tolerances and the rings are capable of sealing without much run-in, the regular oils are fine. If not, the non detergent oils allow high areas to wear and the particles to drop into the pan instead of being suspended and overloading the filter. New cars just don't need this kind of treatment. Why piston aircraft engines do, I'm not sure. Maybe because they run really hot and can warp somewhat, and the manufacturers want the engine's internals to learn to work together.

Re: mineral oil
 

Exactly!

Car manufacturers today can machine engine parts with tolerances so fine that the engine is practically ready to rock with no 'break-in' at all. Therefore no break-in oil is necessary for most new cars.
But if you get an engine rebuilt (bored, honed, new pistons & rings) by anyone other than NASA's machinists, you WILL need to break the engine properly in with 'break-in oil' -which have to be mineral oil as delucat2 pointed out.

Freestyler

In aircraft piston engines, where tolerances are not as tight, straight mineral oil is used for the first 50 hours or oil consumption has stabilized to ensure proper seting of the rings and bearing surfaces.

In new Mercedes, the machining is so much more exact that they are now factory filled with Mobil 1.

So Mercedes Break in oil is just Mobil One
 

Thanks Ali
You answered my question with what I expected.
Most likely there is no special break in oil. The term is just often used by lay people to point out the oil is origional and has not been changed.
-- On another note regarding oil.
I am the 2nd owner of my ML320.
The 1st owner told me he added a quart of oil every 1,000 miles or so since new.
When I got it at 90,000 miles - -(6,000 miles since last oil change) it went thru a quart every 700 miles.
Then I changed it 2,000 miles ago and the oil level is fine with no adding of Mobil One.
The only things I have done is...
1) cleaned the EGR Tube
2) as mentioned changed the oil
3) used Mystery oil in my gas
4) I use Mobil Premium Gas. Previous owner said it took Regular Gas. (so 90,000 miles on the wrong octang)
It's a mystery to me why the oil consumption went way down.

Steve,
If you are feeling nosey, all the oil info, changes, at what miles and number of quarts added are recorded in the instrument cluster. If you inform a dealership of a possible oil consumption problem you might get the info at a cheap rate.

Clairification - Please recorded in instruments ?
 

So you are saying, everytime I add a quart of oil, there is a sensor that records it. Not to mention oil changes.
I can hardly imagine.
There must be sensors in the crank case or oil pan all the way from bottom to top.
I did go to the dealer and get the records on the oil changes.
Never occured to me to ask for the record of quarts added.
Thanks for the enlightenment.

UPDATE 1-27-04
Dear Paulwho-
Thank you for the well of information.
Hopefully I will grow to appreciate this Mercedes as much as my Honda's.

sdanville,
One sensor about 3" tall in the sump records oil level to the millimeter and analyzes the oil condition.