Min once a year as per the owners manual.

 

New and used cars sit on dealer lot for several years and it never gets changed. But yes, change it once a year at least

 

Why would you not want to change it at least once a year? Cost of oil change vs cost of a ruined engine makes the decision simple. If the environment is you issue just make sure the used oil is recycled. Can't see any reason for not changing it at least once a year.

 

The question is not, "Is the oil still good?", because it is. The question is how much moisture is in my oil denying lubrication to critical parts because of displacement of oil molecules?

 

 

 

I've put less than 700 miles on mine in the last 15 months. I am not going to change it till the fall. I personally don't need to feel good about taking 700 mile M1 out of my car yet regardless of the time or the "recommended" 12 month time frame. It's your car, you decide.

 

I'm with the others, no harm in spending the few bucks to change oil. If you wait, your engine will not be ruined. Your choice.

 

Moisture in oil really isn't a huge problem because the first time you take a long trip the oil will get hot enough that the moisture will burn off. The bigger concern would be if you get fuel in the oil as that is a bit harder to get out of there. But you typically don't see a lot of fuel in the oil unless you have a leaky injector or if you're getting blowby through your rings.

 

The idea behind the one-year spec is that condensation builds up in your oil pan and contaminates the oil even when it isn't being used. OTOH, I keep my garage at <75% humidity by running a dehumidifier, and I doubt if condensation is a problem when humidity is kept at these levels. I have a C2 that rarely gets driven and I justify keeping the oil in it for longer than one year on that basis. I think if you live in a humid part of the country like I do and the car isn't kept in a garage where there's some control over humidity, you may need to think about condensation issues as they relate to oil-change intervals.

Additives in oil can handle a certain amount of contamination from water, which combines with the sulfur in fuel to produce sulfuric acid, and that function is reflected in the TBN (total base number). This number starts high (6-9 with most new oil) and decreases as the contaminants are absorbed. This can be determined in a given oil sample by having it lab tested and the oil is ready to be changed when the TBN gets below three.

 

People always believe what other people are saying. If you put low miles on your car each year and it is easy miles and you want to throw your money away , it's your money so change it every year. There is no difference in the oil sitting in your oil pan during the winter or a five gallon jug sitting on the shelf. It's all about miles unless you start your car often and run for short periods during storage and create moisture that gets into your oil . You wouldn't throw the oil out that sat on the shelf for a year. People didn't change oil at yearly intervals years ago and oils today are far superior , especially the synthetics so do what makes you feel good , it's your money.

 

The real idea behind the one-year spec is a time based reminder.

Many years ago, and some still think this way, manufacturers and oil companies promoted oil changes at 3,000 miles or 3 months. When cars didn't have full flow filters and oil had no detergents, that was SOP. It also was a time when you used different weight oil in the summer than the winter and you rebuilt the engine well before 60,000 miles.

Fast forward 50-60 years and we have far better oils and engines easily capable of 100,000 miles with minimal maintenance. We also have systems that can more accurately determine the "half-life" of engine oil. The "half-life" is when your DIC shows 0% remaining, which is also the calculated point where the dis-advantages of the deterioration of additives outweigh the advantages. It is not the countdown to the point where your engine becomes a timebomb and will explode without notice.

However, most people only pay attention to the gas gauge and rarely cycle through the remainder of the information available. The DIC readout is permanetly set on XX MILES REMAINING. Since the average annual mileage is 12K and the average driver never runs high RPM, oil will last a year without significant adverse effects. Anniversaries of events, that include car purchases, are much more memorable, which is why all manufacturers use the 1 year oil change as the time based interval.

Although, if it makes someone feel better to adhere to a spec in a manual designed for the average driver of the average car, then by all means, make yourself happy.

 

This makes sense for low-milers like the OP.

But obviously, once-a-year might not be enough for cars that are driven a lot.

 

This is the first car I've owned with a DIC oil-life indicator and I'm reluctant to accept its recommendation on face value alone. Not all oil is created equal and I'll probably use a 5k or 1yr criterion, whichever comes first, like I have for about 15 years on two of my three vehicles. My C2 has oil that I last changed in 2008, but has only logged about 200 miles in that period of time, so although that interval may be a bit too long I don't feel the need to change every year in that car.

I think oil has improved so much over the last few decades, like cars and tires, that conventional thinking no longer applies--like the 3000-mile oil change ritual I lived with for a very long time. A few years ago Car and Driver said "tires have gotten so good over the years you almost don't need cars." That might also apply to oil in a tongue-in-cheek kind of way, as they too have improved greatly over what we had in the 60s and 70s.

So do you and most others here tend to follow the DIC's oil-change recommendation? Since I probably won't put 5k on the car in an average year I will probably go with a one-year interval, unless the consensus among this erudite crowd (not joking) is to follow the DIC or some other criterion. OTOH, it might be good to follow the one-year or 7500-mile recommendation during the warranty period at least.

 

oil breaks down & turns acidic, you may want to change it once a year.

 

 

 

The cost of a oil change is nothing compared to having to replace or rebuild the engine, My 2 cents.

 

^ exactly...cheap insurance.

 

I put less than 2K per year on my 04 and I change it every January almost on the same date.