By Tom Torbjornsen
I have three questions: What would happen if I added regular air to a nitrogen-filled tire? Where do I get this done and how is nitrogen added when the tire loses pressure? What is tread separation?
I ask these questions because the service writer at my Lexus dealer told me that I had a tread separation because somebody added air to my nitrogen-filled tires! Is there any truth to what he said?
Joseph from Queens, N.Y.
The answers to your questions in order: If you add regular air to a nitrogen-filled tire, nothing happens other than negating the benefits of the nitrogen.
Any facility with a nitrogen tire-filling station can add nitrogen to your tires with a hose and air chuck.
Tread separation is a term used to describe the separation of the tread from the carcass or body of the tire. It is usually caused by poor curing of the rubber during the manufacturing process (a defect).
Finally, tread separation CANNOT be caused by adding air to nitrogen-filled tires. I have never heard of such a thing! If this were true, think of the liability issues the service industry would be exposing itself to by offering nitrogen filling. Earth's air (which we pump into most tires) is made of about 78 percent nitrogen and we have been filling tires for a very long time. There is no basis for this ludicrous statement by this uninformed service writer.
I own a 1995 Chevy pickup with a 350 engine. When I let my foot off the gas the engine still runs fast, as though the gas pedal is sticking. I checked it and it seems to return to its original position after I press it. What could be the problem?
Tom from Troy, Mich.
I did a little digging and found that GM issued a recall on your truck for throttle binding. The recall is number 96V057000 from GM. It involves checking for proper dash mat clearance of the throttle cable. If there is improper clearance then the tech will cut some of the dash mat to allow proper throttle cable clearance. That should solve the problem.
I own a 2008 Subaru. Do you know of any defect in the seals around the windows? When I wash the car, the windows stay wet for days. When I roll them up and down I can tell that the water is not draining out. I left the vehicle outside one day when it rained and I had the same problem. Can I get Subaru to correct the problem? Any help you could give me would be appreciated.
Deb from Westhampton, N.J.
I looked through all the 2008 Forester TSBs and came up with nothing. It sounds like the door drains are plugged up. Have a tech remove the door panel and inspect inside the doors for dirt, insulation, or rust. All three conditions could plug the door drains. I do not think you will get Subaru to do anything because it is not threatening to life and/or limb. Sorry for the bad news.
The car dealership tells me the squeaky brakes on my 2009 Toyota Sienna van are safe and the pads look good. Is it true that replacing the brake pads is no guarantee that it will cure the squeaking? Any ideas? I find the sound to be so embarrassing.
Frances from Rome, N.Y.
Yes, that is true with semi-metallic brake pads. You can change them, cut the rotors, insulate the pad steel backing and still, after all that, end up with squealing brakes. Try changing the pads to ceramic brake pads. Ceramic pads tend to be very quiet compared to semi-metallic pads. Just make sure that you turn the rotors and install new shims and pad insulation as well as the anti-rattle clips. Hopefully, this will eliminate the offending squeal. I wish you success.
I can hear a low hissing sound in my 2010 Cadillac DTS when I press the brake pedal. It's not there while driving, only when I hit the brake. What is the cause?
Chad from Forest Hills, Ga.
Have the power brake booster checked. It sounds like there is a ruptured booster diaphragm. Basically, the brake booster is a giant vacuum servo that has constant vacuum pulling on it. When you press the brake pedal, the vacuum assist makes for easy brake pedal application. If the diaphragm has a hole in it, you will hear a hiss inside the vehicle when the brake pedal is depressed. Success to you.
Finally, a letter from a reader at AOL Autos who read a recent article I wrote on oil change intervals:
Like you, I have been involved with automobiles since Baxter was a boy. In the old days, when oil was really cheap, I worked in a gas-station garage after school to get money to pay for gas. The old rule-of-thumb was fresh oil and filter every 1,000 miles. As you have changed your ways with the improvement to petroleum-based products, I must concur that I too feel better knowing that at 3,000 miles my trusty and beloved motor will be getting a clean drink of filtered juice. I guess the saying stands about old dogs and new tricks. I love the smell of a clean, freshly opened can of oil.
Eddy from Barr Harbor
'Til next time ... Keep Rollin'
Find Tom's new book, "How To Make Your Car Last Forever" in local Barnes & Nobel booksellers. Find it online at Amazon.com.
For more articles by Tom Torbjornsen, visit AMERICA'S CAR SHOW website at americascarshow.com.
Tom Torbjornsen is an automotive expert of 37 years. An automotive journalist in good standing with the IMPA (International Motor Press Association) and MPG (Motor Press Guild), Torbjornsen is the Repair and Maintenance Editor for AOL Autos, At Home Portals, and many other websites. Hear his radio show AMERICA'S CAR SHOW, locally on AM1340 WKSN via the SSI Radio Network Saturday mornings at 8. Listen to the show on the live stream during regular show times at americascarshow.com. Send your car questions to his website at americascarshow.com.