How often to change synthetic oil?


I’ve been using synthetic since i got my yaris a year ago, party due to cartalk recommendations, and partly due to the guy at Sears who talked me into it. The first Sears guy said it would be fine to bring it in every 5000 miles. Another guy there told me, no, it was imperative to bring it in after 3000 to keep the engine in the best shape. When looking for the answer on the internet, i found someone who changes his synthetic oil every 25,000 miles and it was doing great. I know, i know, just look at the color and decide the best time, but i have so much to do right now that i won’t get around to checking the oil any time soon, and wouldn’t really know the best color anyway. How many miles do you think would be best?


I’ve been using synthetic in several of my vehicles over the past few years. I stick to a 6000 miles change schedule myself. It may be too frequent or not frequent enough, but I could also wreck and total my car tomorrow. 6000 works for me. I’d recommend choosing an interval that works for you and not worry too much.


To preserve any warranty that you might have you have to change your oil according the manufacturer?s schedule. They only good way to determine when your oil really needs to be changed is by oil analysis.


Use the interval prescribed in your owners manual.


Read the owner’s manual and follow what it says, synthetic or not. Same for filters. You really can’t tell by looking at the oil. Buy synthetic for additional protection, not longer change intervals.


It is generally agreed that if you are going to change the oil every 3-5,000 miles you are wasting money using synthetic. Regular oils will provide more than adequate protection. I suggest you read some of the discussions on for additional insight. These guys are really anal about oil and you can see the results of used oil analyses as well as read somewhat educated opinions.


I have a friend who uses synthetic oil in his Toyota pickup. He has used it since 100,000 miles, now it has 250,000 miles on it. He uses Mobil 1 (I think) and changes the filter every 1000 miles, tops off the synthetic a quart, and never drains it. Still running. Go figure.


You folks aren’t going to like this, but I’ve been using synthetics since mobil 1 came out in '76, and I’ve typically gone 10k to 15K miles, and a couple of times 20K, without a hint of a problem. Currently, I plan on 12k changes.


Start with the manufacturer’s recommended change interval. If you feel more comfortable using a shorter interval, it won’t hurt anything (just costs more). I wouldn’t exceed the manufacturer’s recommendation without performing an oil analysis (about $20).


If your driving is mostly freeway and/or if you change cars often enough, then that could explain this.


My owner’s manual does not differentiate between regular and synthetic oil. Extended driving range was an early marketing ploy to justify the extra expense for synthetic oil. It was successful as it stuck in people’s minds.


I’ve typically gone 10k to 15K miles, and a couple of times 20K, without a hint of a problem.

What kind of a hint of a problem would you expect before the damage is done? Oil problems tend to cause long term expensive damage.


No, I don’t change cars often. I take them to over 130,000 miles. When mobil 1 came out, some Ford engineers put some in a new Lincoln off the assembly line as an experiment. They ran 100,000 miles without a change, only adding as needed. When they stripped the engine down, it appeared to be factory new.