Myth if the engine had previously been at least basically maintained.  The
only problems come if it was a severely neglected engine with a lot of crud
built up to get dissolved by the new oil. Then a flush is recommended even
if you don�t change to synthetic oil. You may develop a drip you never noted
before but has probably been there all the time.  This is something that has
been tested out by numerous labs.
jimt

On 8/25/05 6:48 PM, "Rob" <becida@COMCAST.NET> wrote:

> At  8/24/2005 11:53 AM, Larry Alofs wrote:
>> Personally I would use 20/50 only if I felt the oil pressure was low.
>>   Before I went to Mobil 1 (15W50), I used 15W40 Rotella T from Shell.
>> 
>> I use 15W40 in all my vehicles other than my vanagon.
>> 
>> Larry A.
> 
> I've heard that it's not a good idea to change to synthetic oil in a
> high mileage engine.
> Any thoughts on this?
> 
> 
> 
> Rob
> becida@comcast.net
> Western WA state with no VW right now... but I'm looking
> 
>