3,000 miles or 3 months?

I’ve recently started telecommuting (working from home). Because of this wonder of awesomeness, I don’t drive nearly as much as I did before, so this question came up:

Everyone always says “You should get your oil changed every 3 months or 3,000 miles.” This, of course, is based on the old NADA (or whoever came up with it) estimate that the average person drives an automobile 1,000 miles in a month. However, if you drive far less than 1,000 miles in a month, do you need to still get the oil changed every 3 months? As it stands, it’s been almost four since I’ve had the oil changed, but have only traveled some 800 miles.

operative word is …“should” some will say yes others will say wait…my "05 RAV manual states every 5000 miles or 3 months…drive it 7000 miles/year and change it once/ year maybe twice…what does your manual say for extreme conditions? Your decision, your car…oil and filter is cheap…

This depends really on what kind of car you are driving and what kind of oil you are using. I am willing to bet that you are using the standard Pennzoil, so I would go ahead and replace every 3 months.

Just like you said, a lot of the recommendation comes from the standard 1000 mi/month. However, here is the catch: Today’s oil is a lot better than it used to be- the oil contains “antioxidants” (a term I hate to use because I associate it with biological systems, not mechanical ones), meant to protect engines from oxidation. These antioxidant additives are generally only good for about 3 months, hence their recommendation.

If you really want to do right by your car and not have to change the oil as often, get some Mobil 1 Extended Protection- it is what you should be using anyway and it would even be cheaper since you don’t have to replace it as often. Synthetics outclass the old world oil in every way. If you use Mobil 1, I can almost guarantee you that you will not have an engine failure (typically something else will give out long before then- like the transmission).


While this sounds like an excellent plan, I’ve heard a lot of dissuasion against using a synthetic on a vehicle that has been running with standard for any length of time. Since my Silverado is a 2002, I would consider that a length of time. Or am I misinformed about that?

If you have the owners manual use the severe interval in time.

Without any manual every 4-6 months seems like a good balance.

There’s a book in your glove compartment. The people who wrote it know more about your engine than “everyone”. Check it out sometime.

I interchange conventional, semi-syn, and synthetic based on my economics and availability, so I would not consider this an issue. I have seen no changes in oil consumption when I do this in my older cars, so it is a non-issue with me.

My manual says 6 months is fine. I would not do 3 months, unless you have a very unusual situation that’s too frequent. Also “everyone” doesn’t say 3 mo/3000miles, most folks here say to read your manual. What does it say?

I would look hard for sound technical reasons to extend your oil change interval(if it does say 3mths 3000miles,severe duty parameters met), you probably will find them. Start with the manual then give a call to those that wrote the menual.

The changing over to synthetic from standard oil is an absolute myth. There is no basis for this myth that still pervades the auto tech world. Go over to Mobil 1 Extended Protection and change it only once a year. You’ll be glad you did when you have the car 15 years from now.


If anything about that is true, it’d be switching to regular oil for an engine designed to run full synthetic, such as turbo/super charged engines, or higher end cars like BMW, Mercedes, etc.

Thank you all very much for your suggestions. I’m going to check out the book, but I believe that I’ll probably get it changed every 5 to 6 months, if the books lists that as an appropriate ‘severe’ time table. Thanks again.