The premium lubricants I use have a 35,000 mile oil drain interval on 5
quart systems.  Acids formed from sulphur by products are neutralized by the
lubricant for well beyond that period in gas engines.  Diesels require
periodic oil analysis to determine the drain interval due to soot
contamination and higher acid formation.  I was able to go 40K between oil
drain intervals on my Rabbit diesel with oil analysis.  Pretty cool.  I
considered bypass oil filtration for my 89 Westy like that used on heavy
trucks but reduced in size but it was not practical for these gas engines.
35K is plenty.  I change it once a year anyway.
TEMiller
----- Original Message -----
From: "Robert Cardo" <rrecardo@WEBTV.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, June 07, 2005 9:12 AM
Subject: Re: Hydraulic Lifter Week

> . <<They way far exceed anything that the engines of the 80s were
> designed for. Far more stabilizers for low and higher temperature
> ranges. For more additives for both stickiness and slip. If your using a
> quality oil on those engines you could easily get away with that
> schedule>>
>
> I agree on the superior oil technology.
>
> However, with only a 5 quart oil capacity
> I sure wouldn't want the acid and sulphur by products of internal
> combustion laying inside my engine.
>
> A class 8 truck has a 15 gallon oil capacity, and the recommended oil
> change intervals are at 10,000 miles.
>
> You suggest that with a 5 quart capacity leaving that garbage inside the
> crankcase?
>
> Thank you--not me.
>
> Oil changes are the cheapest and most redeeming maintenance anyone could
> possibly perform on their vehicle.
>
> I'll stick to the 2500--3000 mile interval's.
> It has proved rewarding may times over.
>
> I have never had any lifter, stuck ring, or bearing problems, and always
> get big trouble free miles out of my engines.
>
> 10,000 mile oil change intervals---
>
> Oh Yea.
>