Jump to content

The RennTech.org community is Member supported!  Please consider an ANNUAL donation to help keep this site operating.
Click here to Donate

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

Recommended Posts

I don't mean to poke a bear here.  It is just that I see many differing values quoted around the site for oil change intervals.  


I believe the Porsche owners manual says changes should happen at 20,000 miles.  In posts, here and other sites, I have seen recommendations from 2,000 to 15,000.  


I have had the occasion to break bread with people who design motor oil additives and motor oils.  They seem like they really know what they are talking about.  I expect that Porsche know what they are talking about as well.  I am familiar with Porsche's leather tanning and finishing standards and they are extremely high,  I expect they care more about their oil.


I am not trying to be inflammatory, I just really want to know.  Why (specifically) do people believe that the oil needs to be changed so frequently?  


I am not talking about running the car on the race track.  That is obvious.  However, the 911 is know as the best daily driver supercar for a reason. Lots of us drive them like cars.  For those instances, what is the proper change interval?  I am really interested in the experiences that led you to that recommendation.  Also, does it vary by the specific engine.  (Mine is the MA1.01)

Link to comment
Share on other sites

  • Moderators

It all depends upon how long you expect your engine to live, and how much of the marketing "Kool Aid" that oil producers and car manufacturer's spout you are willing to swallow.  The optimum method to determine when the oil should be changed is by monitoring the used oil's TBN (total base number), which indicates how far gone the additive package is at any point.  When the TBN drops from virgin levels to 50%, it is time to change the oil.  You should also be looking at contaminants that collect in the oil, particularly fuel and water.  Those of us that collect this data, and spend most of our lives inside these engines, will tell you 5-6K miles is about it.  Beyond that point, the oil is falling out of grade (no longer the advertised weights), its film strengths are significantly diminished, and the contaminants start to become corrosive to engine components.

  • Upvote 2
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.