Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Change the oil after 600 miles?

In June 2009 while I was unemployed I bought my neighbor’s 1985 Porsche 911 Carrera Cabriolet for my wife’s birthday present (she can’t drive a stick, but has a very willing driver living with her). The oil was changed just before we bought the car. We drove it 200 miles in 2009, and 400 miles last summer. The question I have now is whether we should change the oil, even though we’ve only driven the car 600 miles since the last oil change. I’d rather avoid the inconvenience and cost of the oil change.

Oil change is just one of several maintenance services that should be scheduled every X miles or X months, which ever comes first.  I am going to guess you don't have an owner's manual so which would tell you want those X's are.  So I would recommend once every 6 months/1,000 miles which ever comes first.  I might doubt the mileage recommendation if you are using synthetic oil. 

However if someone can give you the original recommendations, I would stick to them.  I suspect that if you do some googling you will find a list somewhere that can give you the Porsche recommendations. If so follow them.

It certainly would pay for you to obtain an owner’s manual. These are readily available, either from Porsche or from online reprints. You will want the manual for a myriad of other questions.

The cost of an oil change is trivial. Many of us do it ourselves, and you ought to at least learn how. I recommend you change the oil now even if it may not be totally necessary. Give yourself peace of mind.

This is an air-cooled 911 correct? I would think it would be wise to change the oil on a yearly basis even if you don’t drive it enough to rack up the usual amount of mileage, especially since the oil plays a part in the cooling of this car’s engine. You have an exotic car, failure to perform routine maintenance will result in exotic repair costs.

I agree that you should change the oil at least once per year. And drive it more often. Why own it if you aren’t going to use it?

Sounds like it’s time to change the oil. Thanks for the feedback, everyone.

If the oil looks clean on the dip-stick, why change it?? Motor oil has a very long shelf-life…

This is a joke, right? You bought a Porsche when you were unemployed and two years later you are worrying about the cost of an oil change?

Oil shelf life in sealed bottle from the factory in perfect state if one thing.

However inside a motor with an amount of moisture present inside the motor oil it degrades and loses its ability to lubricate.

Would you a drop of water to motor oil, leave the cap on loose and use the engine oil a year latter?

To be fair, it IS 26 years old

One more reason to change the oil: if you want to sell this car next week/month/year/whenever, the buyer will want to see the maintenance records. Skimping on oil changes will reduce the price you can get when you sell. This is especially true of 911s, whith the combination of high maintenance requirements and picky buyers.

I have always doubted the time lapse aspect of oil viscosity. How is it possible that oil, in it’s crude form, lasts hundreds of millions of years without losing it’s properties of stickiness to metal, yet once refined to motor oil, needs to be replaced every 90 days? Even gasoline, a much more refined form of oil, combusts well enough long after ninety days.
But then again, I don’t drive a Porsche 911. If I did, I’d change the oil every 90 days however many miles I’d driven.

“How is it possible that oil, in it’s crude form, lasts hundreds of millions of years without losing it’s properties of stickiness to metal, yet once refined to motor oil, needs to be replaced every 90 days?”


Say what?

If the oil has not become contaminated, it does not need to be replaced… Sitting in a garage, motor oil will last for many years… There are no insidious forces at work contaminating it, the crankcase is more or less sealed…

How many quarts with that oil change? Rocketman

Which means it’s even more expensive to repair and maintain. I think Oldtimer’s question stands.

It was run for 600 miles. Contaminants got in and have been degrading the oil ever since.

And there’s probably elevated metal particles in the oil because if he’s only driven it 600 miles in 2 years, he probably doesn’t start it that often which means increased wear when he does start it.

You could send an oil sample out to be tested and see if it’s still serviceable. You could do this every year until the lab says it’s time to change it. This could take many years at your rate of usage…

Oil obsessives have a special web-site all their own called Here you can find the services offered by several oil testing labs…