UKKid35

Until recently I had my oil changed at 3k intervals, but a combination of laziness and reading Doug Hilary's posts has meant that it has been 12k since my last oil change (isn't that the factory spec OCI?)

Never Again. Not only am I not going to risk another Exxon Valdiz incident, but I'm never leaving it that long again. What came out was horrible, and believe me I've spent enough time wading through it to be sure that I made a mistake leaving it in the car so long.

bigs

I change my oil once a year so far. But then I only drive the car 3-4K miles a year.

Garth S

Once yearly.
Appearance changes during usage is a misleading guide to oil quality - the extreme visual may be a fresh change in a diesel: within a 100Km, some go to jet-black. Very small amounts of emulsified combustion by products start to look quite ugly, despite being well within the capacities of the detergent/etc. additive packages.

deliriousga

Every 6000-7500 is when I will be changing it once she's back on the road and the daily driver. That'll be about every 3-4 months. I believe the manual calls for 7500. In the Boxster, it's every 13-15K miles. The manual actually calls for every 15K with a filter change only every 30K, but I do the filter at every oil change in case there are metal fragments hanging out in there and waiting to get loose.

Mobil 1 has a new long-life that is guaranteed for 15K miles, no matter what the manufacturer calls for. Only problem is you have to use the Mobil 1 filter (if it's made for your car) and other filters don't last that long so you'd have to drain it anyway with the filter.

Since seeing the Consumer Reports tests a few years ago, I follow the manual. They drove 2 each of several different models 100K+ miles. One of each model they changed every 3K and the other when the owner's manual said to do it. At the end, there was no difference in internal engine wear.

Bill 86.5 928s

I'm lucky if I log 2000kms in a year. I only change it once in the spring, around May 1st and retire the vehicle Nov 1..........Bill

Dennis Wilson

Mine is a daily driver with about half the time in stop and go traffic. Also I have a few short trips per week, so it's every three months or 3K miles between changes.

Dennis

Thaddeus

2-3 K miles, Mobil1 only. The daily drivers: every 3500 miles, Mobil1.

I like clean oil and won't use anything but synthetic. I expect my cars to start when it's 30 below and the synthetic makes that a lot easier and a lot less damaging.

UKKid35

I've used Injector Cleaner a couple of times, doesn't this quickly contaminate engine oil?

Bill Ball

Once a year or 10-12K miles for my 89. I just checked the manual, and it calls for 15K miles or once a year (7.5K miles for turbos). The 3K mile oil change is an oil company marketing program, unless you use cheap oil. My car is driven regularly (almost daily) and isn't left outside overnight (avoiding condensation). Do oil analysis if you aren't sure.

Garth S

The better ones, like Techron, use polyester amine based detergents, and often higher aromatics such as xylenes: all this stuff only enters the combustion chamber after it is 'atomized' with the fuel ready for the big bang. The concentrations are very low ( say 500 ml in a 50l fill up =1%), and they are both volatile and combustable; therefore the cleaners burn off quite well.
It is more likely any unburned residues blast out via the exhaust valve rather than being washed down the cylinder wall by the engine oil.

Chuck Z

Once per year with Mobil 1.

wino5150

Sorry, I'm of the addage....oil is cheap...wear on the engine is not. That being said, my only concern is the natural oxidation and breakdown of oil over time. If you read the synthetic oil sites, they heartly recommend long change intervals, but I have a problem leaving oil in my engine longer than 4 months or 2500 miles. I'm probably wasting money, but at least I know that my oil is 'like new' and I'm adding an extra hundred or two dollars at most to my maintenance costs. Bottom line is, despite all the hoopla (me being one of the guilty) all of us who drive the car within it's limits have very few oil related problems. That just goes to show that large capacities and excellent engineering have made this car very forgiving on it's oil damage and wear.

Good driving,

Roland

WallyP

Once a year, in the spring.

If I were storing the car for the winter, I would change the oil just before I stored it.

Shane

I store my cars twice a year, and change the oil in both right before I put 'em to bed. I also use dino oil as synthetic has a tendancy to drain off all the upper components and leave them unprotected during a long storage period.

heinrich

As the manual says, every 7500 miles. My Mobil One looks and smells fine but clearly a bit used at that mileage.