Is it mandatory to change oil once a year?

Question

I drove only 4000 km in a year. Volkswagen advises that I change the oil in 15,000 km kilometers or 1 year. In this case, what do I need to do, because I have driven only 5000 km.

Answer 1

It's 15,000km or 1 year, which ever comes first. If you only go 4,000km in 1 year, then you should change the oil at 1 year.

Answer 2

To add to what @BrianKnoblauch said, there are other reasons why I wouldn't let it run that long. The main reason is the additive package which is delivered in the oil breaks down over time. Once the additives breakdown, the oil will no longer clean like it's supposed to, nor have the viscosity variance we see in multi-weight oils. Once this happens, your engine will start seeing greater wear, which over time adds up.

EDIT: Something I did fail to mention is if your vehicle is under warranty, you will want to absolutely follow the manufacturer's guidelines if you expect to maintain the warranty. If you don't care about it, it becomes much less of an issue (I do not see most people letting the manufacturer off like that, though).

Answer 3

Full disclosure: I'm no expert on oils, this is just some of the information I've gathered from researching on my own.

To add to what @Paulster2 and @BrianKnoblauch said, one of the reasons a time and mileage are both specified has to do with the what happens as the oil is used and as it ages. Part of the oil's job is to neutralize the by-products of combustion. As the oil is used, these by-products start to contaminate the oil. The more contaminated the oil is, the higher the acidity becomes and the more potential for corrosion to your engine. Another thing that happens at the oil ages is oxidation, which again raises the acidity of the oil.

To get an idea of how much life is left in the oil, you can take a sample of the oil when you change it and have it analyzed. Blackston Labs is a popular choice.

The analysis can tell you, among other things, what the viscosity is currently at (it will usually be a little lower than the virgin oil) and it can tell you the total base number, which relates to the oil's acidity and ability to neutralize by-products. There are other test that give you an idea how much of the "cleansing" additives are left, and all of this together will give you a very good idea of how much life is left in the oil. Consequently, this information will tell you if you could have gone longer or should have changed it sooner.

If you do this with each oil change, you can easily come up with a maintenance schedule for your particular vehicle/conditions/oil choice.

Another benefit is if you do regular oil analyses you can often spot engine wear before it becomes a catastrophic failure. At $20-30/oil change, it's pretty cheap insurance to invest in.

See here for some good reading on the subject Bobistheoilguy

Other than that, I would stick with the manufacturer recommendations.

Answer 4

Things to consider are oil breaks down over time. Gas, or water that gets into the oil forms acids which increase engine wear. The cellulose, or paper in your oil filter also deteriorates over time. I have a pickup which I drive 2000 miles, or less per year. I went with synthetic oil, and use the best oil filter I could find. (Mobil 1 oil filters) I feel relatively comfortable changing my oil once per year. I am considering going longer, but I want to find more information about the safety of doing so, before I extend the interval. If you use regular oil, I would recommend every 6 months. I know that seems excessive, but engines are very costly to repair, or replace.

Answer 5

It is not mandatory ( in the US) , it is just foolish and dumb not to . A major reason is the low driving mileage . Low mileage implies short trips which is the most severe conditions for motor oil. Short trips promote water build up in the oil ; A long ,hot drive gets the oil hot and gets the water out. Many engine oil additives are added to prevent corrosion by this water. Taxi cabs can run 100,000 miles without oil change because they run so much they never get water condensation . It was done with Super Permalube (not synthetic) , an Amoco product, in the late 70's. Before internet and may not have been published anyway. Railroad diesels do not change oil, they basically run all the time so no condensation ; They do require testing for dilution by fuel and they do require that additives be replenished from time to time. But if you want to gamble a $ 2500 engine replacement against a $ 25 oil change , roll the dice.

Answer 6

If you are driving a new car, or your car is under warranty I wouldn't risk it, as some sensors might malfunctions, due to code error, however if you are driving an old car that has no leakage, and the color of the oil is still yellowish, time is not important, but would recommend changing it after 2 years, even if the oil is yellow, and you drove less than 5k.

The reason why you should change the oil after two years, isn't because of the oil is breaking down, it's because the oil filter not design for a long period.

Engine oil deteriorate sharply during the first 200km, then deterioration is much lower, regardless of time, another factor you should bear in mind the way you drive, if you do a lot of donuts, 5k is too much, even if you changed the oil a week ago.