Brake Pad, ABC and Check-Engine Warning Lights - 2005 Mercedes-Benz CL65 AMG Long-Term Road Test

2005 Mercedes-Benz CL65 AMG: Brake Pad, ABC and Check-Engine Warning Lights

February 9, 2015

2005 Mercedes-Benz CL65 AMG

When last we reported, our 2005 Mercedes-Benz CL65 AMG was back in the shop. It was there with three warning lights:

  1. 1.Brake pads
  2. 2.Active Body Control (ABC) fault
  3. 3.Check engine light

The day after our CL's flatbed arrival, the dealership sent us this $16,000 estimate for repairs. Take the jump to see what happened next...

Rather than call to ask why our CL65 was there, the service team at W.I. Simonson Mercedes-Benz first performed a once-over of the car. The above estimate was the impact on our wallet, were we to okay everything it thought needed attention. This was somewhat expected, as we knew this routine from the last time we brought the CL65 here for service. But this was the largest number we've seen on that bottom line before.

Step 1, once we caught our breath, was to review the estimate. Step 2 was to decline the unnecessary repairs and focus on the actual reasons we brought the car in for service. Three systems displayed faults and those were what we wanted fixed. After 18 days in the shop, here is what we learned.

2005 Mercedes-Benz CL65 AMG

Brake pads: The estimate recommended new pads and rotors, front and rear. The cost was $3,100. We asked a few questions of our advisor and learned that, "the sensor was triggered by the rear." So we replaced only the rear pads for $402.

2005 Mercedes-Benz CL65 AMG

ABC fault: A hose burst. Two lines leave the ABC pump, which doubles as the power steering pump. One goes to the control valve block which then distributes fluid to the four corners of the system. That blew the last time. The second line runs to an intentional dead-end, which acts as a damper for the system. That blew this time. A replacement was order and installed for $1,920.

2005 Mercedes-Benz CL65 AMG

Check-engine light: Our car had 10 stored engine codes when it arrived at the dealer. This list translated to: All cylinders were misfiring except 11 and 12. I am starting to think engine codes should include $ in them, like restaurant ratings: $ = you'll make it, $$ = postpone vacation another month, $$$ = leave the key and run. We asked that the tech spend time diagnosing the problem rather than throw parts at it, which is sometimes the dealer's troubleshooting approach. His time cost us $907. He determined that the spark plugs were to blame so we swapped all 24 plugs (2 per cylinder) for $1,157.

2005 Mercedes-Benz CL65 AMG

The plugs from cylinders 1-10 (above) were 72,000-miles old and exhibit what would be considered normal wear. It made sense to change them, especially since the maintenance manual suggested it around 60,000 miles. But there was a surprise.

2005 Mercedes-Benz CL65 AMG

On the left is an example of one of the normally worn plugs. On the right are the plugs from cylinder 12. They look similar. However the residents from #12 are aged only 6,400 miles. Surprise! A closer look by the tech located valve stem seal leaks in #12 that appeared to be the cause. There were similar but less pronounced leaks in #11. The cost to replace all valve stem seals was quoted at a rate of roughly four semesters at community college. We passed.

Our test is now officially complete and it's time to sell. This CL65 could be yours. Go ahead, make us an offer. Please?

Total Cost: $4,586.72

Total Days Out of Service: 18

Mike Schmidt, Vehicle Testing Manager @ 72,035 miles

2005 Mercedes-Benz CL-Class

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