Oil Change; Spring, Fall, or Both?

[KerryM]

I've been restoring a '78 Targa for a few years now. I wrench on it during the nicer weather and store it in a heated barn from around November - March. I only put about 750 - 1000 miles on the car each year.

Would you recommend changing the oil when I retrieve it from the barn, or just before I tuck it away for the season? Both seems a bit of an overkill, but perhaps not.

[Schulisco]

Anybody has its own opinion on this. Some people say replace the oil after the season and before putting it in the barn, others have opposite meaning. 1000miles is not that high mileage to be concerned. The more miles you had driven over the season I tend to change it afterwards and to store it with fresh oil, as we're talking abount acids and carbon residues floating in the oil and may cause damage. But the car must sit much longer with old oil to have a serious impact on this. Keep cool and when you want to give the car some love, change it before putting in the barn. The oil doesn't suffer when sitting until next season.

[Otter74]

I think that if you change the oil once a year (since your low mileage will lead to changes based on time), it's not that important when in the year you do it.

[PeteKz]

Neither.

See Blackstone Labs' web page. There's an article about this question. Short answer: Oil does not wear out or go bad with time, but with use. I do not change oil on time, only on miles. I run oil sampling on my cars (not just the 911). I typically change it about 10,000 miles, at which point, the tests indicate the oil still has plenty of life left (low contaminants, low metal wear, correct viscosity, and high TBN).

That said, DON'T drive the car a little bit at a time, with old oil or new oil. You will build up water vapor and volatiles in the oil that will lead to corrosion if it sits for a long time. If you drive it, get it fully warmed up (for an hour or more) before you put it into hibernation.

If you change your oil at low miles, you not only waste money, but you also throw more crap into the recycling stream and eventually into the environment. If "green" is important to you, use the full life of the oil (or reasonably close to it) before you throw it away.

[gled49]

Im with Peter, on my air cooled cars every couple of years. 5000 miles on our work cars. I’m not an annual oil changer.

[HarryD]

I change my oil every 4-5000 miles whether it needs it or not. I do not use a calendar.

[KerryM]

Thank you for all of your good comments. I changed the oil mid summer this year so, depending on the miles, I will wait at least to the end of next summer. I'm planning on putting a lot more miles on the car next summer; if I hit a total of 5,000 miles I'll change it then.

The barn is about 45 minutes away, and I will take the long route to make sure it is fully warmed up.

[PeteKz]

Kerry, just for fun, when you hit 5000 miles, take an oil sample and send it for analysis. Then decide whether to change it. Oil analysis is about $35. Oil change is $100+?

[ryans65]

Oil is cheap, change it often! 10k interval is nuts!

[PeteKz]

What data do you have? I have the oil sample results from 10 years of doing it on various cars. But don't take my word for it. Go to Blackstone Labs website and search for their recommendations. .

[Magyar Kiwi]

Hi PeterKz
Like your approach to oil changes based on us (miles) only. (Post #4)
What is the longest calendar time it has taken you to accrue the 10,000 miles triggering an oil change ?
Thank you.

[PeteKz]

In the 911, about 2 years. In one of my other cars 3 years.

[Synchro Joe]

Originally Posted by Otter74

I think that if you change the oil once a year (since your low mileage will lead to changes based on time), it's not that important when in the year you do it.

This, annually regardless and brake/clutch fluid every two years. Works for me, and my 1988 is nearing 200k miles.