srs4

Hey Guys, hoping to pick anyones brain here. I had my '06 S4 rebuilt and its seems like the break in process did not go so well. From what I understand, the mechanic made a mistake and put in synthetic oil after the rebuild and it would seem that the rings did not seat properly. Did a compression test and I am 120psi across all 8 cylinders. Any suggestions on what I might be able to do to save me from doing another rebuild? Perhaps a thinner oil to get some friction back and hopefully re-seat the rings? Going through about 1 qt / tank of gas right now. Appreciate any help!

Cheers

DrGP

You get one and only one opportunity to get the pistons to seat properly. Then you live with the consequences. While I admit, in a best case scenario, a non synthetic oil should be used for break in. Every S4 engine comes from the factory with synthetic oil in it. What is most important is how you drive the car initially to enable the rings to seat completely. Driving the car gently does not get the ring to seat properly. Driving it like you stole it does, But IMHO, that technique puts undue stress on other engine parts. I always advocate the Motoman technique or a slight variation of it. Those of us who have tried it, know it works and will not do it any other way. FYI, for the first 5k miles, engine wear is your friend. After that, engine wear is the enemy of all engines. With synthetic oil, it just take a little longer for the rings to seat. But after 1k miles, your ring are not likely to seat much further if at all. You didn't say how many miles you have put on the car since the rebuild or how you drove it. PERHAPS you might want to put in some non synthtic oil and do WOT runs to the redline followed by engine braking back down to cruising speed. Not from a dead stop, like a drag race, but from 5mph. Do not worry about taking the engine to the redline. If it is rebuilt properly, nothing bad will happen. In fact, a 6MT car can go over 7200 rpms before the rev limiter cuts off fuel. With a DSG trans, you will never get the engine over 6500 rpms regardless of what you do.

growl2

So, this topic has been beaten to death. I can not comment on how to deal with your current situation but I can comment on how to break in a new or rebuilt engine. As has been documented on this forum, the motorman method is flawed. All the points DrGP makes, needing pressure and undue wear ESPECIALLY ON A NEW ENGINE by running to the redline are correct. Someone a while back posted a very thoughtful article that I believe was in Popular Mechanics and it was based on science and not anecdotal evidence of a few people on a forum. What it says it, you do need to run at WOT once warmed during breakin, HOWEVER, to not let the engine initially get above maybe 3000rpm. As miles build, you can start to increase thenshirt point. High revs are likely to prematurely wear a new engine but pressure from WOT does help eat things. Also, to be clear, engine warm is not coolant temperature up to operating level, it is oil temperature up to operating temperature. This takes maybe 15 minutes on a warm day. Hope this helps. So motorman has the right issues, the solution is off though.

DrGP

But it still works.

growl2

You actually don't know that. Given the number of S4's out there, we don't have anything close to a statistically significant sample to make that statement. We also have what is likely dramatic bias in the sample.

Finally, a significant number of oil burning engines will negatively impact resale value of a brand. Having good resale is critical to offering competitive lease prices. Do you believe that Audi, who does have the data, would not modify their break in procedure if it resulted in higher resale.

DrGP

No I don't. All Audi cares about is selling the new car. They make no more money if the resale cost is higher. Trade in cost would be higher for the owner making any additional resale value a wash. Audi sets their residuals low to begin with.