Sludge and lubricants

[Grant Lenahan]

mostly agreed. I've posted pages and pages on oils on various sites. But my point is that while the synthetic base does not deteriorate as quickly (mostly due to fewer VI improvers), they still lose good additives like anti-foam, anti-wear, detergents, anti-acid, etc.

And acids and petroleum distillates do build up. So even if you had perfect, permanent, last into he next century synthetic oil , you sould still either change it or become a formulator and add your own additives, then take the oil out and centrifuge out the impurities.

So the fact remains, they can be extended, but even synthetics require changing by 1 year or ( it varies) 5-10k miles.

I would avoid 20k on any car that uses oil hard, such as a 1.8t.

For instance, a car like my boxster or S6, with > 8 qts in the sump, can go longer than a 1.8 with 4.3 qts in the sump.

I would never go 20k

Grant

On Nov 1, 2010, at 4:40 PM, Scruggs Family wrote:

> Grant, while your comment is correct it steps over one of the vital reasons
> for using synthetics... they have far less additives than petroleum bases
> lubricants.  Petroleum oils typically have 20% of their volume in viscosity
> improvers, pour point depressants, antioxidants, etc.  Synthetics... the
> good ones... have a little as 5% of the same additives.  Essentially, with
> synthetics there is less in the mix to wear out and contaminate the
> lubricant.  
> 
> I first used synthetic oils in '77 in my Rover 2000TC.  I've used synthetics
> exclusively since '85 (even in the lawn mower) and have had no problems,
> noticeable wear or increased consumption using 20k mi change intervals.
> That's about 600kmi over 6 cars/trucks.  I do, however, change filters every
> 5k and top up the level.  
> 
> Gross Scruggs
> Annapolis MD
> 
> 
> Message: 1
> Date: Mon, 01 Nov 2010 14:45:09 -0400
> From: Grant Lenahan <glenahan at vfemail.net>
> Subject: Re: How to check for sludge ?
> To: Ed Kellock <ekellock at gmail.com>
> Cc: 'thejimrose' <thejimrose at gmail.com>, quattro at audifans.com
> Message-ID: <4CCF0AB5.1050002 at vfemail.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> yes, they do. But bear in mind that oils deteriorate for many reasons, 
> and even with synthetic you must consider:
> 
> 1. depletion of additives
> 2. accumulation of acids
> 
> Neither is affected by teh improved base stock
> 
> Grant
> 
> 
> 
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Grant Lenahan
glenahan at vfemail.net