Dear Doctor: I am interested in a Mini Cooper S however, a problem has been brought to light on the Internet forums; carbon buildup on the back of intake valves. Apparently, the direct injection does not allow for fuel to flow over the back of the intake valves, cleaning PCV deposits, and carbon builds up there. Is this true of all direct injection engines? Is there a way to prevent this from happening? Is blasting the deposits with walnut shells (at $800 a treatment), the only viable remedy? -- Tom
Dear Tom: Around 50,000 to 70,000 miles is most common for carbon buildup and faulty timing chains. If there are no symptoms of misfiring and upper engine noise, then a simple top engine cleaning is all that's needed annually. If there is carbon buildup causing problems, then sometimes a double dose of cleaning will remove the carbon. If not, then the manual cleaning will be needed at the expensive cost of $600 - $800. Use good quality fuel injection cleaner, not the cheap ones. Using one can every other tank fill-up will also help clean the valves.
Dear Doctor: I have a 2002 Chevy S10 pickup truck. The ABS and brake lights are indicated sometimes. Diagnostic codes called it an intermittent EBCM problem. What do you advise? -- Don
Dear Don: Sometimes ABS lights codes need to be checked when the check indication light is on. If needed, the ABS electrical part of the brake module can be overhauled and rebuilt. A new unit can cost over $1,000. If you do not want to make any repairs the brake system should operate just as a vehicle without the ABS option.
Dear Doctor: We currently have 38,000 miles on our 2008 Honda CR-V. The vehicle is maintained well: new brakes, tires, battery, air filters, etc. I'm told by the people who service my car that I should have the anti-freeze completely drained from the radiator, along with the transmission completely drained. What are your thoughts? -- Barry
Dear Barry: I'm all for the draining of the fluids on this vehicle. I would use only manufacturer-recommended fluids. We use only OEM transmission fluid and antifreeze on our services. You can also change the power steering fluid and brake fluid using a turkey baste (use a separate baste for each fluid, do not mix them). Do not cross-contaminate the brake fluid.
Dear Doctor: I have a 1999 Mercury Sable V6 with 97,000 miles on it. I replaced the original steering pump because it was leaking. A month later it started to whine occasionally. I brought the car back to my mechanic to check the noise out and he said the steering pump was fine. A month later the steering fluid was leaking from the steering fluid container (out the top of the container) and whined when turned. The car went back into the shop and the high pressure steering line was replaced. Recently, the steering container started to whine and leak again from the top. Is something binding in the steering system that is causing the fluid to back out the top of the container? -- Tom
Dear Tom: Older front-wheel-drive Ford power steering pumps can sometimes make a whining sound, but still operate normally. Leaking is uncommon. The power steering pumps are usually rebuilt, not new. I have had good luck with both Ford and aftermarket pumps. I also found using the correct power steering fluid -- not automatic transmission fluid -- works best. Have the technician check hoses and flush out the lines and rack.
Dear Doctor: I have a 1999 Toyota Avalon. A code reading came up P0125. The possible problem area is open or short in Air/Fuel sensor circuit, A/F sensor malfunction, and PCM malfunction. I've already replaced the oxygen sensor (bank 1). After replacing the oxygen sensor I cleared the code with a OBDII monitor. The car runs fine for two weeks, then the "check engine" light appears with the same code. Please guide me through the diagnosis. -- Deepak
Dear Deepak: The fault code is for the air ratio sensor or rear oxygen sensor. Look at the code in the freeze-frame mode; this way you will be able to look at all sensor information. I researched your issue on Identifix and see many hits with faulty heater relays and poor connections. Even a faulty mass air flow meter can cause this code. -- Junior Damato, Motor Matters
Junior Damato is an ASE-certified Master Technician. Email questions to email@example.com. Mail questions to: Motor Matters, PO Box 3305, Wilmington, DE 19804