How long is it safe to drive on a compact spare tire? | Car Doctor
Q: I recently had the spare tire put on after having a flat tire. The gas station said I could drive on it for a long time, but my neighbor said I should drive on it for just a short time. It is one of those small tires. Who is right?
A: Compact spare tires are really meant for emergencies and are designed to get you to a tire store to have the original tire repaired. With a temporary spare tire, speeds should be kept below 50 miles per hour.
I would not drive on a temporary spare tire for more than 100 miles. Temporary spare tires are smaller and can affect the ABS braking system as well as traction control operation.
Also, depending on the vehicle, driving on the spare for a long time can potentially damage the transmission if mounted on the drive axle, since the two tires are different sizes.
Still, as inconvenient as a temporary spare tire is, I would rather have any spare tire than no spare tire.
A checklist to prepare your vehicle for a long road trip
Q: I have a six-year-old Toyota Highlander with 60,000 miles. I am planning a cross-country road trip. It will just be my husband, me, and our dog. What should we do before the trip? What about emergencies?
A: I recently drove nearly 2,000 miles. Here's what I did:
I changed the oil and checked all the vital fluids, drive belts and hoses.
The tires on the car are only about a year old, but I gave them a good look and inflated them to the proper pressure.
My car has a spare tire mounted under the car. I lowered it, lubricated the winch mechanism and adjusted the air pressure.
I also checked the brakes and suspension components, replaced the wiper blades, filled the washer fluid and checked all the lights.
I kept a quart of oil, extra washer fluid and coolant, the old wiper blades, some basic tools, a portable air compressor, a battery jump-pack, flares and a first aid kit.
Periodically during the trip, I checked all the fluids and topped them off as needed.
Enjoy the drive!
Can oil additives harm the engine?
Q: I recently was watching a YouTube video about oil and saw a scientist talking about how oil additives – and even mixing oil – can cause issues with engine wear. I know you have mentioned products such as Lucas oil treatment and Marvel Mystery oil in the past. Is there really a danger in using these products?
A: Some of these products just change the viscosity of the oil, and that can help with oil consumption and free up sticky valve lifters. The issue is that some additives can mix with the additive packages in oil and have a negative effect.
Personally, on a good-running engine, I'd use a quality oil and filter, change the oil periodically as recommended by the manufacturer and check the level every 1,000 miles or so and add oil if needed.
Listen and learn more about oil from Sean Nguyen, an oil scientist from Pennzoil, on my radio program: tinyurl.com/4k69date.
What's the cost of rebuilding the engine on a 40-year-old Mercedes 190SL?
Q: I have had the pleasure of driving my Mercedes-Benz 190SL for more than 40 years. The wear and tear on the car have taken a toll, and the engine finally "gave out." It has been "throwing" oil for years and now, when I attempt to start the car, antifreeze comes out of one of its cylinders.
I know the engine needs to be rebuilt. I have found someone who has been working on 190SLs for eons and knows them inside and out. He said he would be willing to undertake this task, which is great news for me. However, he advised me that the cost to rebuild the engine would be between $25,000 and $40,000. Being retired and having a limited income, I was surprised by this estimated cost. Is his estimate reasonable? Any insight you can provide would be greatly appreciated.
A: Based on your description, the car has a cracked block or at least a cracked cylinder head. To completely rebuild the engine without looking at damage to the block and cylinder head, I would estimate the cost in the $12,000 to $15,000 range. But with the variables of replacing the cylinder head and possibly the block, certainly $25,000 or more is possible.
Specialty shops, such as Metric Motors, at one time had complete rebuilt engines for $15,000 (plus shipping and return of the old engine). Add in any extra lines, mounts, clean-up of the engine compartment, and perhaps replacement of the radiator, fluids, belts, hoses and miscellaneous hardware, I can see $25,000 certainly being a starting point from a specialty shop.
John Paul is the AAA Northeast Car Doctor. He has more than 40 years of experience in the automobile industry and is an ASE-Certified Master Technician. Write to John Paul, The Car Doctor, at 110 Royal Little Drive, Providence, RI 02904. Or email [email protected] and put “Car Doctor” in the subject field. Follow him on Twitter @johnfpaul or on Facebook.
This article originally appeared on The Providence Journal: Is it safe to drive on a small spare tire? | Car Doctor
