Good Car Care Advice from Tom T - #5

Tom Torbjornsen, host of "America's Car Show" radio program answers questions from his listeners. (Listen to Tom's radio shows every Saturday and Sunday right here on The Auto Channel)

Dear Tom, I recently drove through a huge puddle of water. The car made it through the puddle but shut down afterwards. I own a 2003 Mercedes c240 with low mileage. All the lights turn on and everything works when I put the key in the ignition, but the car won't start. Any thoughts? Steven from Jacksonville, FL

Steve, Knowing full well the dramatic intensity of rainstorms in your neck of the woods, there are a couple of possibilities that come to mind. A module or wiring harness could have gotten wet, shutting down the ignition system. If this is the case, the vehicle will start again when it dries out. If this is the cause of the shutdown, I recommend that you go over the ignition wiring and apply silicone insulator to the connections and plugs to prevent it from happening again. Depending on how much water you drove through, there is another possibility. Water could have been sucked up into the air intake, filled the cylinders, and hydro-locked the engine with water. This can be checked by manually cranking the engine with a socket and breaker bar on the harmonic balancer. If the engine is hydro-locked, remove the spark plugs and crank the engine. Clearing the engine of water should allow you to start the car again. Success to you. Tom

Dear Tom, I own a 2002 GMC 1500 pickup with 4WD. I was told not to use studded snow tires on the rear of the truck, along with the two light truck tires in the front, because this will damage the transfer case. What are your recommendations? Chris from Derby

Chris, You will NOT have a problem running a set of four identically sized tires and studding the rear only. The key is to make sure all the tires are the same diameter. Mixing tires that are different sizes causes transfer case damage. Different size tires turn at different rates of speed, thus causing the differentials and axles to twist against each other at the center point of the drivetrain (the transfer case). By maintaining the same size tires all the way around you ensure that the driveshafts all turn at the same rate of speed. Tom

Dear Tom, I own a 2001 Nissan Sentra, and there is a problem with the brake pedal. Occasionally, when I'm waiting at a traffic light, the brake pedal goes down about a half-inch or more, as if there is a loss of vacuum (doesn’t go all the way to the floor). Have you ever heard of this occurring? Paul from Nashville, TN

Paul, I would check the master cylinder for an internal leak. Fluid is probably bypassing the main hydraulic valve, causing the pedal to drop when pressure is applied sitting at a light. Hold your foot on the brake and see if the brake pedal fades or drops to the floor. If it does then the master cylinder is probably leaking internally. Another option would be to remove the master cylinder and inspect the rear seal. When the master fails, there is evidence of brake fluid leakage on the rear of the unit. Best to you. Tom

Dear Tom, I own a 2002 Honda Odyssey. Lately, the gearshift won't move until I pump the brake pedal a few times. I just bought this car and I am concerned. Should I be? Jacques from Casper, IL

Jacques, You need to have the brake interlock system checked out. There is a switch located at the top of the brake pedal linkage that unlocks the transmission from park when you step on the brake. When it goes bad, the vehicle is difficult to shift out of park. If the switch checks out okay, then the wiring for this circuit will have to be traced and repaired. Good luck. Tom

Dear Tom, I own a ‘95 Ford Contour 6 cylinder. Whenever I drive the car there is a humming or roaring noise in the front that gets louder on acceleration. Also, whenever I make a turn there’s a popping or grinding sound more pronounced on one side. What’s wrong? Jeffrey from Lancaster, PA

Jeffrey, The humming noise is probably due to a bad wheel bearing, located on the side where the sound is emanating. It needs to be replaced before there is a safety issue (when wheel bearings separate, the wheel can fall off). Check the bearing and if it’s good then the noise could be coming from the differential and should be checked. In reference to the popping noise, the vehicle probably has a bad ball joint. However, there is one other possibility. The coil spring on the side that’s popping could be bad, so have it checked out. Ford issued a recall on several of their vehicles for failure of coil springs in salt belt states, so your vehicle may be involved. Call your local Ford dealer and have the VIN checked. The repair might be covered under recall. Success to you. Tom

Dear Tom, I own a ‘93 Lumina and the brake warning light is lit. When I apply the brakes at a stand still, the engine RPMs fluctuate. When I let off the brakes, the engine runs fine. What could be causing this problem? Sam from Syracuse, NY

Sam, Try this procedure: With the engine running, lift the hood and have someone inside the car apply the brakes. When the engine starts running poorly, pinch off the vacuum line going to the vacuum brake booster using a pair of pliers. If the engine smoothes out, then the brake booster is leaking vacuum and will need to be replaced. Another telltale sign of a leaking brake booster is a hissing noise. Does it sound like a snake is hissing behind the dash when you step on the brakes? If it does, then the brake booster is probably leaking internally. Tom

‘Til next time…Keep Rollin’

For more articles by Tom Torbjornsen, visit AMERICA’S CAR SHOW web site: www.americascarshow.com

Tom Torbjornsen is an automotive expert of 37 years. An automotive journalist in good standing with the IMPA (International Motor Press Association), Tom is the Repair and Maintenance Editor for several websites.