dealer = stealer?

[mewing]

In the latter part of December, I took my '92 500E (219K miles) in for a timing chain and rails, which eventually led to more work. The quote was a total of $3400, and my bill was $3900+, so I was not too happy at that time. Since then, I have a bad oil leak. I rationalized that the oil light coming on at almost 220K was due to my being due for an oil change, and my car probably should burn a little at that mileage. I topped it off at that time. Then, it seemed wet chen I changed my oil at 220K, but again, I rationalized that it could have been from some spillage from when I topped it off, or even the "seeping" power steering pump, which the dealer said to wait and change later. At just over 221K, my wife drove the car, and when she pulled out of the garage, I saw a large (30" in diameter) puddle of oil. I crawled under the car, and it was so wet I couldn't tell where the oil was coming from. I took it to my independent mechanic, who took off the distributor cap cover (maybe not the right part name), and cap, and showed me with a mirror that the leak was coming from behind the timing cover. At that time, my independent mechanic did not know that the dealer had done all that work just two months prior. The dealer said to bring it in Wednesday AM, which I did, and they didn't look at it until Thursday (today), and say they still don't know where the leak is coming from.

My post is for the purpose of getting some insight as to what the problem might be (I know you cannot see my car). I am suspicious that the tech at the dealer had never worked on a 500E before (they took twice as long as quoted, and supposedly a "senior tech" drove the car home for the weekend before delivering it to me - to make sure everything was OK), and may have had problems with the repair. I am afraid they are going to tell me it wasn't something they did, and they will want to charge me my other arm and leg for more work. The reason I am concerned is, when I went back to question why the bill was $3900+ on a $3400 quote, the response was no concern, and I was told the extra $$ was for "miscellaneous." Also, the service rep said his supervisor was out of town, and not available.

BTW, the car did not have an oil leak when I took it in originally.

Is there a common mistake made when timing chain work is done that would result in an oil leak like this?

Any ideas?