Oil Change, How often?

[JoeA]

Just got my 1999 996, needs an oil change, can someone just let me know what the interval is?

[1999Porsche911]

Did you get a manual with the car?

[ar38070]

The manual states every 15000 miles or 2 years under "normal" conditions.

[djantlive]

oil change every 15k mi

[LVDell]

7.5K-10K is more realistic with most of our driving styles. You can go to 15K, but I would not follow that interval. Mine is 7.5K per interval.

[skl]

YOu'll get a 100 different opinions here, but I'd never go 15K miles between an oil change. I'm probably more anal than most, but with the 911 I never go more than 4-5K miles tops, but do go a little more than that with the Cayenne. I just changed the oil the first time in that with 10K on the clock, and will probably change more often as I'll be towing with it some this summer.

[ar38070]

As they say opinions abound.

It is interesting to note that for the 987 and 997 Porsche has extended the service interval to 20,000 miles or 2 years.

Personally I change mine once a year or about 5000-7000 miles, but I also track my cars extensively.

[JoeA]

Thanks for all your input, The car did have a manual, I rather ask people with experience. It certainly helps.

[b-man]

I change mine every 7,500 miles.

b-man

[gian61]

On my 996 345Hp I change motor oli every 10.000 Km.

Edited February 28, 2005 by gian61

[DeAd-EyE]

im probablygoing to make a habit of changing the oil once a season (roughly 4-5k kms) while the car is up on blocks for the winter. if you do it yourself its not as hard on the budget.

[x5rap]

No matter what, I can't imagine going more than 12 months without and oil change, even if only 5K miles.

[useridchallenged]

I was frustrated with many of the opinions on oil changes, so I decided to do my own experiment and figure the oil change issues out for myself, independent of all the opinions.

So I did a lot of experiments with synthetic motor oils (Mobil 1, Amsoil) by using the services of Analysts Inc. (Oakland, California) who analyze motor for aircraft and industrial vehicles, where engine life is critical. They report the oil chemistry, viscosity, particulates, metals in the oil, presence of water, and so on. I treat my auto engines like I do an aircraft engine - lots of careful monitoring and maintenance.

What I learned after 70,000 miles with a Mazda Miata (I ran this experiment from 1993 to 1998 before I had my Porsche, and checked the oil every 3,000 miles):

(1) Synthetic motor oil is very stable. The oil can easily go 15,000 miles and still have excellent viscosity, PH and other chemical properties.

(2) Contaminants are the real issue that drives oil changes with either synthetic or regular motor oil. I found that changing the air filters and oil filters had more impact on the motor oil than changing the oil. Because I wanted to check the properties of the oil after 15,000 miles, I had to more aggressively change the filters in order to keep the oil clean enough to go 15,000 miles.

The result for me - I change out oil and oil/air filters every 7,500 miles. If I were on a tight budget, I would consider checking/changing only the oil/air filter every 7,500, and change the oil at 15,000. If you drive in a dusty environment (dirt roads, near building construction, etc.), you will want to change your filters more frequently.

In summary - keep your oil clean. Dust gets in the oil and it acts like an abrasive, wearing at the components in your engine. The only reason to change oil more frequently is to get the abrasive contaminants out. But changing your air/oil filters will accomplish the same thing. Synthetic motor oil is amazing - 15,000 miles is no problem for the oil. But again, the problem is not the oil, it's the contaminants in the oil.

Next experiment (someday) - test the oil right after Track day to see how synthetic oil is affected by hard driving and high heat. Now for an opinion - I always change my oil before and after tracking the car. More habit than based in science.

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1999 C2 Arctic Silver, 6-speed, LSD, TC

2000 BMW 740i Sport, silver ("German Impala" for cruising with the family)

[DeAd-EyE]

^ how does this apply to leaving ur car parked for the winter. for instance in my case:

i get about 4-6k kms a year on the car then it goes in for the winter.

i was going to do an oil change next week and will probably bring the car back out in april.

should i do the oil change every season because of contaminants that might stick to pistons and whatnot over the winter, or should i just change the oil filter every winter and oil every 2 years?

Off-Topic: what's the usage life of BMC F1 filters?

[LVDell]

As I stated I do 7.5K miles between changes of oil and filter. I have tossed around the idea of doing filters at 5K intervals and oil at 10K intervals. Sounds a bit more on track as to what should be done.

[useridchallenged]

^ how does this apply to leaving ur car parked for the winter. for instance in my case:

i get about 4-6k kms a year on the car then it goes in for the winter.

i was going to do an oil change next week and will probably bring the car back out in april.

should i do the oil change every season because of contaminants that might stick to pistons and whatnot over the winter, or should i just change the oil filter every winter and oil every 2 years?

Off-Topic: what's the usage life of BMC F1 filters?

<{POST_SNAPBACK}>

4-6k kms per year is nothing for the filters or the oil. I dry year-round, so I haven't given winter storage any thought. I might be concerned about water vapor condensing in the engine during storage and mixing with the oil. For that reason alone, I'd change the oil at the end of winter storage. But I haven't done any experiments to test this theory of water condensation, and water condensation during the winter will have a lot to do with the temperature and humidity of your garage.

[DeAd-EyE]

But I haven't done any experiments to test this theory of water condensation, and water condensation during the winter will have a lot to do with the temperature and humidity of your garage.

garage is heated 24/7 at about 65 or 70 degrees F. Humidity seems pretty low but i havn't had an opportunity to check it. probably wouldn't hurt to throw a dehumidifier down there once in a while. then again, i'm probably just being cheap.. trying to avoid a 50 dollar oil change on a 100,000k car thats been flawless upto this point.