Do you change your oil too often?

Hey there, time traveller!
This article was published 21/10/2016 (3594 days ago), so information in it may no longer be current.

QUESTION: I keep hearing that synthetic oil is better and lasts longer than regular oil. If this is so, why does the manufacturer of my vehicle require an oil change every four months or 8,000 kilometres? After one year I still haven’t reached 8,000 km and was required to have four oil changes. I’m just wondering what your opinion is on the situation. Ray

Answer: The manufacturers base their oil change intervals on average driving patterns, which for Canadian drivers is 20,000 km per year. You’re obviously driving much less than this.

There are two reasons for changing the engine oil.

First, it wears out, or as some say, “breaks down.” Oil molecules consist of long chemical chains, and as the engine operates these chains are cut or broken. The shorter the oil’s chain, the less protection it provides moving engine parts. Additives can be added by the oil manufacturer to help reduce this breakdown or improve the protection capabilities, as oil from different parts of the world has different-length chemical molecules when it’s just a base oil. Synthetic oil chains are more durable, but they do break down over time.

The other reason for changing oil is to remove impurities in the engine that are trapped in the engine oil. This includes water and acids formed by the combustion process, carbon, unburned fuels and metal particles. If an engine is left to sit for long periods of time (several months), the acids in the oil can eat into the internal engine parts and cause premature wear.

Synthetic oils are better at protecting the engine in extreme heat or load conditions while also providing quick flow and lubrication in very cold weather starts. However, they still collect impurities in the oil just like conventional oils.

I like synthetic oils because of the protection factor, but they’re definitely more expensive. As for oil-change frequency, routine maintenance such as an oil change is necessary to ensure new-vehicle warranty. In your situation, you are well below mileage change intervals and I’d recommend dropping your changes to a couple a year — one in autumn and another in the spring. Winter is the hardest time on oils, as engines experience colder starts and more driving where the engine doesn’t warm up completely. If you weren’t driving in the winter, you could probably get by with just doing an oil change every 8,000 km.

 

Question: I was in a small accident with my Chevrolet Malibu and had it repaired at my local body shop. This happened about two weeks ago and involved repairing the hood and grille. Everything looked good after the repair but now I’ve noticed that the remote start on my key fob doesn’t work anymore. It worked this past summer but I hadn’t used it until the weather started to get colder this week. The only work I have had done to the car was at the body shop so I took it back to them to see if it was something they did and they said no — it was only a minor repair and they didn’t even disconnect the battery. Is the remote start problem a coincidence or do you think the jar from the accident caused other problems?

Answer: I don’t think the hit from the accident caused other problems, but the repair may have caused your lack of remote starting. The remote starter is designed not to operate if the hood is open. This protects someone who may be working under the hood if the remote starter button is pressed.

A switch in the hood latch signals the computer and starting system to indicate if the hood is open or closed and either this switch was damaged in the accident or has become misadjusted. Many body shops aren’t great with electrical repair, so they may not recognize this needed to be checked as part of the repair. I suspect if you have them adjust or replace the hood latch, your remote start will work again.

• james.kerr@sasktel.net