Cars

How far can you drive on a temporary spare after getting a flat tire?

John Paul, AAA Northeast's Car Doctor, answers a question from a reader whose daughter has to travel 180 miles after getting a flat.

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Q. My daughter got a flat tire on her Volkswagen Jetta. She got the spare tire on, but now must drive 180 miles home. She knows she can’t drive on the spare tire for long. How long can you drive on a temporary spare tire? 

A. Generally, driving on a temporary spare tire should be limited to 50 miles per hour and about 50-60 miles of travel. Temporary spare tires are designed to get you to a service station or tire store. Depending on the condition of the tires, it may be best to replace the damaged tire and the other tire on the same axle. In addition, current thinking is to put the newest tires on the rear of the car. 

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Q. The rear windshield washer in my wife’s 2014 Chevrolet Captiva goes on and stays on after starting up, and runs until it empties the reservoir. After looking at Chevy forums, the popular opinion is a battery harness voltage problem. I had the battery harness replaced and it didn’t fix the problem. I have disconnected the wiper system and replaced the battery. How can I get this solved?  

A. Yes, the common fix has been replacing the battery cable due to a voltage drop issue. If there is no longer a voltage drop and the ground circuits look good, then it’s time to move onto more diagnostic testing. Here is how it works. When the windshield washer switch is pressed, ground is applied through the switch contacts and the windshield washer switch signal circuit to the body control module (BCM) indicating the windshield wash request. The BCM then energizes the relay by applying ground through the control circuit to the coil side of the relay. With the wash relay energized, battery voltage from the fuse is applied through the switch side of the relay and out to the control circuit of the windshield washer fluid pump. Any short to ground or short to power could cause the problem. The BCM could be the issue, but I would want to check with a bidirectional scan tool to see what happens when the washer command is initiated. 

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Q. For a dead battery replacement, I’m told that in addition to a new battery purchase, a memory card is needed to store a code. As the car is several years old, where do I get a code number? Are separate numbers needed for ignition, radio, and air conditioning?  

A. Some vehicles have radios that have anti-theft codes which, when the battery is disconnected, go into theft mode. A code needs to be entered to turn the radio back on. When AAA replaces batteries, we use memory-saving tools to prevent this from happening. As far as the running of the vehicle, there may be a bit of relearn (start/stall), but that will clear up in a few minutes. Some other vehicles also need to have the battery registered using a dedicated tool to the vehicle for proper charging. 

Q. My air conditioner went out on my 2012 Honda Accord. I was told I need an air conditioner compressor kit. The price range is $1000 and up. Is this reasonable?

A. Depending on where the compressor is purchased, the price varies from $200 at an online parts store to $800 from Honda. It will take about three hours to install the compressor and recycle and recharge the refrigerant.

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Q. My 2015 Toyota Tacoma V-6 automatic 4×4 has about 48,000 miles on it. How often should the transmission and differential fluids be changed? I’ve had no problems yet, but I keep my vehicles for a long time.

A. Technically, Toyota only recommends checking the fluid condition and changing if a problem is detected. If this were my truck and I wanted to keep it forever, I would follow the trailer towing guidelines and change the differential, transfer case, and transmission fluids every 60,000 miles. 

John Paul is AAA Northeast’s Car Doctor. He has over 40 years of experience in the automotive business and is an ASE-certified master technician. E-mail your car question to [email protected] Listen to Car Doctor on the radio at 10 a.m. every Saturday on 104.9 FM or online at northshore1049.com.

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