[font="]The whole carbon build-up issue really needs a FAQ (IMO). I know it has been discussed on this board, but no strong consensus on the problem has been formed. Since I own a high mileage (106,000) car I worry about this, and everyone’s car is not getting any younger. After reading how much BMW wants to fix this problem ($8000) I really start worrying about this. I understand the labor hours to take the heads off this engine. If we M5 owners can find a solution or an exact cause of this problem we may head off the problems, headaches and expense of this gremlin. I was hoping to get the dialogue going again to try and answer some of the carbon build-up issues and further our learning.
After reading the several posts on this matter I will give it a try, please add, remove or modify the FAQ at any time. The information I obtain is directly from this M5board and I have no other sources of information. I was hoping we could contribute to factual data gathering
What exactly is the carbon build-up problem: Quote from TetherM5 "The SES light came on, they changed the Secondary Air Pump and some O2 sensors. Carbon is blocking the exhaust system causing a low pressure fault on the secondary air system."
BMW cost to fix the problem: BMW has a protocol and handy parts kit to fix this issue. Cost approx $5000- $8000.00
What year models are affected: 2000 and 2001, may have hit a 2002.
What is the percentage of cars are effected by carbon build-up: Don't know. Maybe an informal poll of everyone on the board and we can come up with an unscientific percentage value.
Is there any preventive maintenance or prophylactic procedure to prevent carbon build-up: Maybe several high-rpm (red line) runs will help blow it out. No one knows for sure at this time.
What causes the problem: No strong answer on this question. It may be Oil consumption in older model m62's, bad gas, babying the car??? Please contribute.[/font]