Daily driving the Abarth it's easy to decide when to change the oil, especially with a 26 mile each way journey to work alone. But I realized I don't remember the last oil change for Subarust. It's been quite a few months, but it's been maybe 1k miles.
I know I've heard 3 months/ 3k miles (which I do more like 5k), but how important is the span of time? (The MR2 falls under this question as well)
Vehicles that don't get driven much get changed twice a year in my fleet, spring and fall. Everything else by mileage.
I don't put many miles on my vehicles anymore … so change spring and fall
even though our new vehicles have "oil life" computer read outs … I still change spring and fall
except the TT car … change it every 2nd or 3rd track weekend
Drive the other cars occasionally and get them hot enough to evaporate any condensation. The timespans in question aren't long enough to be significant. If you're talking on the order of years, then yeah. Once a year is mechanically sympathetic.
My Spitfire gets driven very little. I change the oil once a year. I usually change it in the late fall and drive it to get it good and hot, then park it for the winter.
I think my Volt was according to the meter, or every two years. That's probably a special case, admittedly.
My CR-Z is an IMA hybrid. The electric motor and ICE are attached at the crank and don't run independently, so it's more typical. In other words, like a non-hybrid, if the car is moving, you're burning gas.
For that, the maintenance recommendation is by the oil life meter or once a year. I just did an oil change at the one year mark with the "service soon" message up, about 5% shy of the "service due mark." That's after about 9000 miles, with lots of short trips mixed with a couple of long ones. Typically, if I drive further than five miles, I'm going to drive more than a hundred.
The oil was dark. I'm going to get a kit and send a sample off next time, just to satisfy myself that this is sane.
dark usually just means it's doing it's job …or so I've always been told 
With the better oils today, I watch mileage more than time but I like to change it at least twice a year, regardless of mileage. My thinking is that it means I'm getting in there and taking a look at things every six months so I can head off any problems.
I can't even keep up anymore. The Passat tells me when it's due for a change, the rest get it when their oil starts to get dark looking.
In my own experience with engines having oil in them for years and even decades, the worries about acid buildup and bearing etching in old oil are vastly overblown.
I think the time recommendation is as important as the mileage recommendation.... which is not important at all.
Theoretically, things evaporate out of the oil and any moisture sitting in the oil causes acid troubles, but think of it this way:
If the manual says every 3k, that means (depending on driving style) that it might actually need to be changed anywhere from 3k to 30k. No way to know unless you test it, which is why people just go ahead and change it at 3-5k. Same thing goes for time. Could need a change at 3 months or 5 years.
But suffice it to say that the factory recommendations of 3-5k and 3 months are ridiculously conservative. I have run engines that sat for 15 years with the old oil in the pan and they haven't exploded.
That 3 months 3000 miles came about... 60 years ago? Are you really telling me the oil hasn't improved since then, even dino oil?
I go by mileage, unless we're talking about something like a Masarati.
KyAllroad wrote: I can't even keep up anymore. The Passat tells me when it's due for a change, the rest get it when their oil starts to get dark looking.
like I posted earlier .. keep in mind that dark just means it's doing it's business … fresh oil, and several hundred miles (especially an older car) and it should have turned dark
mtn wrote: That 3 months 3000 miles came about... 60 years ago? Are you really telling me the oil hasn't improved since then, even dino oil? I go by mileage, unless we're talking about something like a Masarati.
I'm glad you're not the one taking care of my track car 
I do 3500-4500 miles full synthetic in my GTI because Direct Injection pours so much gas into it when cold and dilutes it. in my Tahoe, dino oil whenever... normally 3500 miles but that's a cheap oil change 2$ a quart x6 quarts and a 4$ filter
wbjones wrote:mtn wrote: That 3 months 3000 miles came about... 60 years ago? Are you really telling me the oil hasn't improved since then, even dino oil? I go by mileage, unless we're talking about something like a Masarati.I'm glad you're not the one taking care of my track car
Sorry, I should have been clearer: I'm talking about a DD.
Since I do oil analysis for a living now..... Most modern oils hold up well. I'm doing a little test with the Forte with Cheapo Walmart Synthetic oil. It's $17 for a 5 qt jug. At 7900 miles, 8 auto-x's and a lot of beating the oil, wear and fuel dilution were well withing acceptable limits. I'm running this another 2k and check again, but I imagine that the base number will be low enough to warrant the change.
Bobzilla wrote: Since I do oil analysis for a living now..... Most modern oils hold up well. I'm doing a little test with the Forte with Cheapo Walmart Synthetic oil. It's $17 for a 5 qt jug. At 7900 miles, 8 auto-x's and a lot of beating the oil, wear and fuel dilution were well withing acceptable limits. I'm running this another 2k and check again, but I imagine that the base number will be low enough to warrant the change.
do you work for Blackstone Lab?
I have a few cars that don't see 3,000 miles in a year. I change the oil in them about once a year, but frankly sometimes it may be 18 months occasionally. I get my oil analyzed by Blackstone pretty regularly, and I've never had any reports showing I was anywhere near borderline for viscosity, insolubles, fuel, water, or any other problem. But cars are different and they may even change over time, so I keep testing - it's cheaper than a second oil change every year, and easier too.
tjbell wrote:Bobzilla wrote: Since I do oil analysis for a living now..... Most modern oils hold up well. I'm doing a little test with the Forte with Cheapo Walmart Synthetic oil. It's $17 for a 5 qt jug. At 7900 miles, 8 auto-x's and a lot of beating the oil, wear and fuel dilution were well withing acceptable limits. I'm running this another 2k and check again, but I imagine that the base number will be low enough to warrant the change.do you work for Blackstone Lab?
No but we do some testing for them that they can't do in house. We're a bit bigger.
Jamey_from_Legal wrote: I have a few cars that don't see 3,000 miles in a year. I change the oil in them about once a year, but frankly sometimes it may be 18 months occasionally. I get my oil analyzed by Blackstone pretty regularly, and I've never had any reports showing I was anywhere near borderline for viscosity, insolubles, fuel, water, or any other problem. But cars are different and they may even change over time, so I keep testing - it's cheaper than a second oil change every year, and easier too.
Oil analysis is perfect for those cases. No need to change it if you don't need to.
Yeah on time alone, maybe once a year to be safe, at most...but mileage is much more important. A few months are nothing.
So it's been sitting underground for MILLIONS of years, but all of a sudden in breaks down in 3 months?
Sorry, not buying it.
If you feel like pouring perfectly good oil down the drain, do it once a year to make yourself feel better. Otherwise stick with the factory recommended mileage intervals (not the 3K intervals that the oil industry wants you to do).
As long as it's getting some longer trips now and then to get the oil good and hot, you can just do it every spring if you aren't putting more than 5000 miles a year on it. That's assuming conventional passenger car oil, more like 8000 on synthetic or diesel oil, maybe more on either figure with analysis.
wbjones wrote: dark usually just means it's doing it's job …or so I've always been told
Since we have oil experts in this thread... what makes it turn dark?
I run synthetic in both cars and do 5k changes. Both are "sensitive" to gunked up timing chain tensioners, and my DD is also sensitive to gunked up oil rings. The Saturn will blacken oil with a quickness. Does that impact it much?
If I could get them down to approx. once/year, that would be great.
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