Carmakers put much thought into correct tire pressure
Q: I purchased a new set of Bridgestone Turanza all-season touring tires for my 2014 Mercedes E350, replacing the OEM Continentals. The installer (Costco) then set the tire pressures on all four tires at 42 psi, although the tire pressure information from inside my car said to inflate the fronts to 33 psi and to 35 for the rears at normal load. I usually take short trips by myself or with one passenger, so I presume that would be a normal load.
I called Bridgestone, and the customer service rep there advised me that 42 psi for all four tires is the correct setting for this particular set. However, when I took my car in for service at the local (Virginia Beach, Virginia) Mercedes dealership, they re-set all four tires to 35 psi and told me that was the correct setting.
I’m retired, and I’m worried about prematurely wearing out this expensive set of tires. — C.C., Chesapeake, Virginia
A: Much engineering and testing go into determining the correct tire pressure. Carmakers consider handling, safety and comfort among other factors. They don’t pull those figures out of the air. (Yeah, weak pun.)
Q: I’m the original owner of a 2009 Nissan Rogue S with 136,000 miles. Been a great car. Last week the remotes failed to lock or open the car. I changed batteries in both remotes — and both still wouldn’t work. I called Nissan service, and they were not helpful. Might there be a fuse that failed? I’m not seeing one listed in my owner’s manual. — M.R., North Oaks, Minnesota
A: The most common problem is a bad key fob battery, but you have already eliminated that. Perhaps the contacts inside the fobs are worn. The receiver module in the car may have failed or your key fobs may simply need to be reprogrammed or re-paired with the car.
Q: I’m having issues with my 2007 Ford Focus. It has 154,000 miles and a standard transmission. It’s hard to shift into first and reverse. I’ve been shutting the car off to put into either of those gears. Most times, going forward I just start in second gear. Also, my car moves when I start it. Usually I have the brake on, but shouldn’t it stay still, if I have the clutch in? Thoughts on the fix for both and estimated cost. — M.E. St. Louis Park, Minnesota
A: Most likely, the clutch is not fully disengaging, it’s dragging.
Two possibilities come to mind. First is a problem with the clutch hydraulic system — either the master cylinder or the slave, which is incorporated with the release bearing.
The second problem is likely the release bearing/slave assembly itself. Make sure your clutch reservoir is full of fluid. If full, you need to take your vehicle to a professional technician. Expect to pay around $800.