Q.I hope this isn’t a silly question. What is the best way to vacuum the interior of the car? My home vacuum doesn’t do a thorough cleaning. The car wash has vacuums, but still I can never get a good cleaning, there always seems to be some sand or dirt left over when I’m done. 

A.There are times you need to use a shampooer and extractor to get the carpets clean. Good detail shops will vacuum up the loose dirt and debris and then use a portable carpet cleaner. The soap and water loosen up the dirt and stains and the vacuum extractor pull out the water. As a DIY approach, mix up some water and dish detergent and then use the suds and a scrub brush. You don’t want to get the rugs too wet, just damp. Once you are satisfied that the carpets are clean then vacuum with a wet/dry vacuum.  If the carpets are still damp, leave the doors open for a bit or even put a fan in the car to dry out the interior. No such thing as a silly question. 

Q.I have an older rear wheel drive car with a V-8 engine and automatic transmission. The car has only 55,000 miles on it. The issue is, the car has a high-speed vibration at 40 mph and 70 mph. I’ve had some shops look at this car and they just can’t figure it out. The tires were checked and are in balance. In addition, I have had the water pump and fan clutch replaced as well as drive belts and harmonic balancer checked. The engine runs great, and transmission was rebuilt. The driveshaft was replaced with a new one, which did improve the situation, but the vibration is still there. 

A.Since the vibration got better after the driveshaft was replaced, I would continue to focus in that area. I would look at drive shaft angle and also put a dial indicator on the drive shaft to see that it is running true. You could also try balancing the driveshaft while it is in the car. This can be accomplished with a couple of large radiator hose clamps using them as balancing weights. If you could find someone with a vibration measuring tool or even an old reed vibration meter it may help pinpoint the vibration. The issue could be an out of balance torque converter or even a poor fit between the engine and transmission. 

Q.I recently purchased a Cadillac XT5 and discovered it has no spare or jack.  The Cadillac dealer says a full-size tire won’t fit in the tire well and compact tires which used to be an optional purchase are no longer available.  I am very uneasy about driving a vehicle without a spare, even if these are run flat tires. Several tire stores I called say they don’t deal with compact tires.  Even some of the local junk yard, “pull-a-part” places were no help. Am I worrying for nothing?  Any suggestions?

A.A run flat tire has a stiff sidewall that allows the car to be driven without air in the tire. True run flat tires will give you the ability to get home, generally 50-100 miles of driving at speed under 50 miles per hour is suggested. Some cars have conventional tires without a spare but include an air compressor and tire sealant. I drive all kinds of new cars, some without spare tires and although I would prefer a spare, knowing that I can at least get to a tire store to fix or replace the tire does make me feel better. Your Cadillac does have mobility kit, air compressor and sealant. This is handy if one of your tires has a slow leak at least you could pump it up to the proper pressure and hopefully get the tire repaired. Still, I would prefer a spare tire, in my opinion even a compact spare is better than no spare tire. 

Q.I have an unusual problem with my 2012 Mercedes Benz E350 4Matic. The car performs great, rides fine and only has 60,000 miles on it. However, when I am driving and take my foot off the accelerator, and then hit the accelerator to resume my speed, there is a sight growl or vibration that lasts a second or two. This situation is intermittent. It seems to happen at any speed. What might be the cause of this situation? I am afraid to go to the Mercedes dealership due to potential costs. Am I in for a big repair bill? 

 

A.I suspect an issue with the all-wheel drive system-transfer case which is an integral part of the transmission.  The condition is sometimes referred to as a judder and will usually happen as you describe while turning slightly and accelerating. There is no easy or cheaper repair if this is the issue. You have two choices at this point, live with it or repair it. If you can live with it, the transmission may last a very long time. If you opt to repair it now, or even when it gets worse it will be expensive. Just to verify what I suspected, I called a local Mercedes dealer to try to get a price and was told to expect to pay at least $5000 for the repairs. 

John Paul is AAA Northeast’s Car Doctor. He has over 40 years’ experience in the automotive business and is an ASE-certified master technician. He will answer readers’ questions each week. Email your car questions to [email protected]. Follow John on twitter @johnfpaul and friend on Facebook, mrjohnfpaul.