Car Doctor: Is extraction method an effective way to change the oil?

Oct 24, 2023

A: In a few new vehicles, oil extraction is the preferred method to replace the engine oil. In fact, some of the mobile oil change companies — to minimize the chance of oil drips — will also use extraction to change engine oil.

On your vehicle, with the location of the oil filter, the extraction method makes sense.

On a vehicle that needs to be raised up to access the oil filter, it is just as easy to remove the drain plugs and drain the oil in the conventional method.

Q: You recently commented that the Chevrolet Bolt, "despite some battery issues, is a very good car." Consumer Reports, in its March issue, gives it an overall rating of 45, which is not good. CR felt the charging rate was also slow compared with other vehicles. Could you explain the differences between your better rating and Consumer Reports' negative ratings?

A: I road-tested the Chevrolet Bolt for seven days and found it to perform quite well. My average driving was about 50 miles per day. I found that charging it overnight at 120 volts was adequate. I did use a level 2 charger once.

Yes, it probably charges more slowly than some other vehicles. I'm not sure about the CR charge rate numbers. The typical level 2 charging rate is 7-19KW, depending on the charging device and circuit. I didn't charge at Level 3, which can charge from 50-350 (Tesla) KW.

Looking at the car itself, I found that, even with four adults, the car was comfortable enough and the storage was fine for trips to the grocery store.

The ride and handling were good, highway merging was effortless, and the nearly 240-mile range was much more than I needed for 90% of my driving.

This in an EV that, in some states (Massachusetts is one), you can buy for about $29,000 factoring in credits and incentives. In addition, Chevrolet will cover the basic installation cost of a home charger. Overall, the Bolt is a good vehicle, but yes, the competition is also good, with some great EVs from Hyundai, Tesla and Kia.

Q: My 2018 Subaru Forester annual inspection was due, and the service is always done at Subaru. The service manager indicated that the engine oil was one or two quarts overfilled. He recommended an oil change to correct the capacity, since overfilling is just as bad as underfilling the oil.

My next recommended service was not due for at least another 3,000 miles, so I declined. It seems that when I do check my oil level, usually, it does measure above the fill mark on the dipstick when serviced by the Subaru dealer.

What effect does this oil overfill have on my engine? With 48,000 miles, this overfill does not seem to have caused any problems.

A: Since you have always had the oil changed at the dealer and it was overfilled by the dealer, it seems to me they should have drained and refilled the oil to the proper level at no charge. Overfilling oil by two quarts can cause excessive pressure on seals and, over time, cause oil leaks.

Q: I have a 2017 Jeep Grand Cherokee with about 52,300 miles on it. The six-year, 60,000-mile warranty has expired due to time, not mileage. The car is in immaculate shape, except for the fact that we were just told that we need a new engine, at a cost of about $11,900.

Three years ago, we took it to the same dealer for an oil change. After leaving, my wife noticed that the oil light came on. She stopped, called the service department and was instructed to return to the shop. When she returned, she was told that sometimes they forget to reset the instrument panel. They did that and sent my wife on her way.

Of course, the lights came on again and the car made bad noises. She went back to the shop. As the car was driven into the area, they noticed a small trail of oil. Sure enough, the cap was not on tight and the engine oil had leaked out. All this is well documented.

Could this incident have caused the damage to the engine? I feel that lack of oil three years ago could have damaged the engine. I would love your thoughts, even if I am wrong.

A: If you have been maintaining the car by the book, that engine should easily last 175,000 to 200,000 miles or more. So, based on the fact that it ran out of oil — or nearly out of oil — it is certainly plausible that the lack of lubrication shortened the life of the engine by accelerating the wear of the bearings.

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.