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The Yankee Express

Q & A with The Car Doctor

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 reader’s questions each week You can find the Car Doctor podcast at or other popular podcast sites. Email your car questions to [email protected] Follow John on Twitter @johnfpaul and friend him on facebook mrjohnfpaul

Q. I recently purchased two Duralast Gold car batteries. They both have removable caps to check water level. I thought I would be replacing the old batteries with sealed maintenance free batteries, but the caps come off to check water level. I had a hard time finding replacement batteries, so I purchased these two. The auto parts store told me that these batteries should never require water added. Can you tell me if that is true, and if not what type of maintenance I need to perform with these?

A. Once upon a time all batteries required water to be added. In fact checking water level was standard procedure during oil change service. Today most batteries are maintenance free. Some batteries are sealed and some, like the batteries you purchased, have removable caps. During the life of the battery most people will never add water to their car’s batteries. Since your batteries have removable caps, there certainly is no harm in removing them and adding water (distilled water only) if the fluid level is low. If you are adding water periodically suspect that the charging system is overcharging the battery and “boiling” off the water. If this is the case, have the charging system evaluated. 

Q. My wife just purchased a 2021 Volvo XC40 T5 R design. We have been told that we can use regular gas in this vehicle. Exactly what grade of gasoline should we be using for this vehicle? 

A. Fuel requirements are typically listed in two ways. The fuel that is required or the fuel that is recommended. In your particular model the XC 40 T5 Volvo requires premium fuel (91 octane or higher). This applies to all T5, T6 and T8 engines, and recommends 93 octane fuel for optimal performance and fuel economy. Volvo recommends (not requires) premium fuel (91 octane and higher) for T4 engines. Volvo goes on to say engine reliability should not be affected as long as 87 octane fuel or higher is used. In the case of your 2021 Volvo XC 40 T5, you should be using fuel with an octane rating of 91 or higher to prevent engine damage. 

Q. With the shortage of used cars, how do I know the car I’m considering buying wasn’t involved in a recent flood? 

A. Here are a few things to look for. Inspect the car thoroughly, look for rust stains inside the car especially around seat brackets. Does the car smell like mold/mildew or does it smell like someone is trying to cover something up? Look in the trunk, under the spare tire. On an SUV lower the spare tire and look for mud and debris. If the spare tire looks like it was just steam-cleaned, be suspicious. A spare tire that has been under a vehicle for a few years should be dusty, not caked with mud or spotlessly clean. Look for water in the headlights and taillights. Open the hood and look for water stains, mud and dirt in nooks and crannies, like the alternator, cooling fan and other surfaces. Check fuse boxes for signs corrosion. Recent rust on unpainted screws indicate moisture. Check all the fluids, if they are milky color this could indicate water contamination. On a warm day, if all of the windows have condensation, this could indicate the interior has been flooded. Finally, when in doubt have a good repair shop inspect the vehicle before you purchase it. And remember what mom said: if the price looks too good to be true, it probably is. 

Q. Headlights are clouded up on my 17-year-old Infinity, what to do?

A. You have a couple of options. The cheapest and sometimes the most effective method is to have the headlights cleaned. You can DIY it with some kits. Some use a buffing wheel that attaches to a power drill, others use a series of very fine sandpaper and then polishing compound. You can also have the lenses professionally cleaned (about $100-$125). Finally you can replace the headlight assemblies with a quality aftermarket part.