I bought my 2007 CLK550 convertible in January. It had 18000 miles and had come off lease last year. I purposely bought a car with some warranty left at least for a few months. The warranty was to expire in June. I live in ATL and flew down to FL to pick up the car. After driving it home I noticed a ticking sound with the car running while standing on the right side of the car by the front wheel. The car drove fine with plenty of power otherwise. I waited about a month and took it to my local dealer. The SA pulled up maintenance information on the car. The car had been serviced by only one dealer in FL its whole life. The thing that jumped out at me was, “too much crankshaft play.” That was all it said, apparently a dealer cannot pull up the actual work that was done by another dealer. So he couldn’t tell me any more about what was done to fix the problem.

The dealership said there were two transmission pumps and they replaced one of them. After getting it home I still noticed the tick but it seemed a little quieter. I thought maybe it was normal. I had a friend come over with an SL550 (same drive train?) and I didn’t notice any ticking sound coming from his car.

I continued to drive the car with no problems, just the ticking. With a month left on the warranty and 22000 miles on the odometer I took it in back to the same dealer in early May. They definitely heard a ticking coming from the engine. They had to get MB authority to do anything with the engine. MB told them to take the engine out of the car and measure all tolerances. With the engine out and the bottom end of the engine off, all tolerances were in limits. After a few days MB told the dealership to take off the heads and see if they could find anything else wrong. MB told my SA what had been done to correct the crankshaft play previously. They had replaced the crankshaft bearings and rod bearings.

After getting the heads off and the pistons out they found the problem. There was abnormal wear in the rear two cylinders on the pax side (cylinders 3 and 4). MB sent an engine expert from Jacksonville to inspect the engine. He was very surprised as was the dealership. My SA said they have very few problems with engines.

Cylinders 3 and 4 showing abnormal wear. You can see the wear in cylinder 3 really well with the way the flash hit it.


Different angle showing cylinders 3 and 4 abnormal wear. There was also abnormal wear at the top of the cylinders indicated by the yellow marks. I could feel the difference between cylinders 3 and 4 and the rest of the cylinders rubbing with my finger tips.


Cylinders 1-4 with 3 and 4 on the left.


Entire engine.


Empty engine bay. What a tight fit.


Notice how high the finder is over the wheels without the engine.




At this point the dealership had the car for 3.5 weeks. My best hope was for a new engine. However, I figured they would get a short block and use what parts they could off the old engine. But, either they didn’t have a short block or they decided against it. HELLO BRAND NEW ENGINE! MB didn’t have any spares in the USA. It would have to be shipped from Germany so add a week to get it to ATL and a few days to get it in and we are looking at 5 weeks without the car. I really didn’t care since I was getting a new engine. The new engine was shipped over and put in. The dealership had to drive it for 100 miles and change the oil then it was time to pick it up. After getting the car back, for some reason I was sitting in the car and thought I heard the tick. It was just my mind playing tricks because I got out of the car and went over to the right side and heard nothing but the engine purring.

Somewhere I had paperwork stating that the old engine was a M272 or M273 and had the bad cam gear. I had been worried about the balance cam gear. I was even planning to pay extra to get a new one installed if they put the old engine back in the car. I figured it would be worth it since they already had the engine out of the car. At least this way I have the newer gear.

Through the whole process the dealership was great, very helpful, and supportive. My dealership is Mercedes Benz of South Atlanta and my SA is Kelly. The dealership was great about giving me a loaner car too. I keep thinking how easy it would have been for either the dealership or MB to tell me there is nothing wrong with the car just to get me to the end of the warranty. I know there are a lot of stories on these forums about how people have been screwed by their dealership or MB but in my case both stepped up to the plate and did the right thing. Thank you MB of South Atlanta and Mercedes Benz. So should I get an exteded warranty?

 

thats great news man....bonus points for MB US... i had a squeling noise comming form the front of my car and took it in multi times and when i got a survey from MBUSA i told them about it and they called me within two days....problem got fixed...i say its up to you i didn't get another extended one but its all a gamble

 

Awesome to hear! Enjoy your new motor!

 

I have been so far. I have been following the new engine break in recommendations. I really haven't noticed any difference except no ticking and worse gas mileage. I know that improve with miles.