Foam in tires cuts road noise

Ask the Auto Doctor

Dear Doctor: I have a 2019 Volvo with Pirelli tires. I recently got a flat tire and the mechanic took the tire off the wheel to patch the tire and he discovered the inside of the tire lined with foam, to his surprise. He removed the foam in the area of the punctured tire to patch it. Why is foam in the tire?


Dear Sarah: The foam is used to help cut down on road noise. The foam has been used for a few years on certain vehicles. More and more car manufacturers, as well as tire manufacturers, will be using foam-filled tires in the years to come. The foam is not related to a tire going flat.

Dear Doctor: I own a 2015 Dodge Dart GT with 66,000 miles. When I press the start button, an error appears in the driver information screen that says, “blind spot alert, unavailable, service required.” When this happens (randomly) the starter will not engage. After waiting for 10 to 30 seconds, the error clears and the car can be started. We’ve had the vehicle to the dealership on three separate occasions and they cannot find a problem and no error codes are appearing. What should I do?


Dear Joe: I checked with Identifix and they list a couple of possibilities for your error code. First, check of the ground circuits, especially the ground circuit inside the left front fender liner. Next, check the voltage on all electrical circuits with a scan tool. A qualified ASE technician should be able to find the source of the voltage problem.

Dear Doctor: My 2015 GMC Sierra with the 5.3-liter engine just turned 100,000 miles. At around 92,000 miles I got a P050d code (cold start rough idle). At that time I changed the spark plugs. I ran a couple of tanks of gas through it, and applied injector cleaner as well. I then cleared the code and it went away. But less than a month later the code came back and this time I started getting a slight miss or stutter at lower speeds when the truck was under load. The dealer said GM told them to ignore the code right now due to the PCM being so sensitive. I’ve cleared the code a few times and it will stay off, but it always comes back. I hooked my truck up to an onboard monitor and it does show misfires on cylinder six. This isn’t enough to set off its own code, but can this be enough to cause the slight jerking or stutter? What is the most common problem with this P050d code? I’ve heard it most likely could be the injector. Or is it possible it’s the coil on number six?


Dear Jamie: The first thing is to get information from the computer on fuel trim and fuel pressure and under what conditions the code was set. I have seen dirty injectors with this issue, especially at 100,000 miles. I have also seen broken valve springs and even a leaking intake gasket contribute to this fault code. The most common fix is a fuel injector replacement.

Dear Doctor: I recently purchased a 2019 C7 Corvette, and I love it. However, when turning with steering wheel all the way to the right or left, the car makes a loud bumping noise and shake (very, very noticeable). The dealership states it is due to the different rotation of the tires when turning. I have had previous Corvettes where this never occurred. Can this be the explanation and can it do any damage?


Dear Steve: The banging sound and thud feeling is completely normal when making tight turns in most high-performance vehicles with big fat tires as the inside tires try to turn at the same speed and distance as the outside tires.

Dear Doctor: Do you have an opinion on the Volkswagen Golf?


Dear Noah: I remember the old VW’s of just a few years ago. They were hard riding and their drive controls were not the best. But I spent a week in a 2019 Golf powered by a turbocharged 1.4-liter hooked to an automatic transmission. The car carries four adults with comfort and the seats are firm and supportive. A large touchscreen shows a clear display with steering hub controls. Under the hood, the turbocharger is mounted off the exhaust manifold and is piped into the intake without the need of an intercooler. Strong power from the four-cylinder engine comes on as soon as the accelerator is depressed. Even from a dead stop under full acceleration the engine is quiet.

Junior Damato is an ASE-certified master technician. E-mail questions for publication to info@motormatters.biz. Mail questions to: Motor Matters, P.O. Box 3305, Wilmington, DE 19804


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