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Oil Change Frequency?


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Just wondering whether anyone suggests changing the oil (mobil 1) more often than once a year. I put on 10K/yr.


2005 Boxster S

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Just wondering whether anyone suggests changing the oil (mobil 1) more often than once a year. I put on 10K/yr.


2005 Boxster S

I change mine and the filter at about 5-6k miles and make no short trips.

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I just finished an oil change on my '08 after 4,000 miles on the oil. I bought the car new, changed the oil at 2,000 miles on the odometer, then now again at 6,000 miles.

A bit of reading on various sites including RennTech will reveal that some of the older Boxster engines have intermediate shaft bearing failures. While it has yet to be determined what exactly causes the intermediate shaft bearing to fail, long drain intervals seem to be the initial culprit. Again, there are no hard facts to prove this theory is 100% correct, but oil is relatively cheap, your motor is relatively expensive, so an oil change every 3,000 to 6,000 miles is good insurance.

These are expensive machines, so regular oil changes could help reduce the risks of developing issues with that intermediate shaft bearing (even though the design was reported to be improved for the model year 2006 and forward). Yes, Porsche recommends a drain interval of 12,000 miles or 1 year (which ever comes first), but if you can DIY, an oil change is about $60 to $80 depending on your source of parts and only about 30 minutes of your time.


08 987

90 964

84 911

Edited by Jay H
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The move towards longer oil changes has been pushed by the government, in an attempt to reduce the amount of waste put into the system each year (which is in general, a good thing). However, longer oil changes don't help when gas and other contaminants get in there. The oil itself is still good, but with gas mixed in, it deteriorates. I suggest 3K to 5K miles based upon many discussions with Charles Navarro at LN Engineering.

Here's a link to my oil change article, if that's useful: http://www.pelicanparts.com/techarticles/Boxster_Tech/02-BASICS-Oil_Change/02-BASICS-Oil_Change.htm


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  • Moderators

First, and perhaps most importantly, I have little regard for most Mobil 1 products, and in particular would not use their 0W-40 product based upon several years of collected UoA's. That said, you should be changing the oil and filter at no more than 5-7.5K miles (2-3K if you insist upon using Mobil 1 0W-40). Much like their "recommendation" for using Mobil 1 in the first place, going 15K is also nonsense, particularly if you use 0W-40...............

Edited by JFP in PA
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Mobil 1 used to be a good product, until Exxon took over. Several grades were true Group IV (PaO based) with great high temp/high shear performance. Then the reformulation began; several grades lost all of their critical ACEA ratings (most notably, the 15W-50, long a mainstay of the air-cooled 911 crowd), and nothing has been the same since. The 0W-40 went from Group IV to III+, to III, to now God knows what. TBN values, long used as in indicator of when an oil should be changed, show that this grade can shear down and is no longer able to "stay in grade" and needs to be changed in as little as 2-3K miles of street driving in something as innocuous as a Cadillac under mild climatic conditions. Not particularly reassuring to someone beating the snot out of their turbo in summer heat.

There are a lot better full synthetic choices available, often at better prices, than Mobil 1. Unfortunately, too many choose not to educate themselves on the topic and merely "parrot" what the OEM "recommends"……………..

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