30,000 mile oil

[isham-research.freeserve.co.uk at pop.pol.net.uk]

>> It's also a good idea to do a proper flush (not just the additive sort)
>> every 100k or so.

> What's involved in this?

Buying a can of flushing oil and following the instructions.

Most oil is mainly intended as a lubricant and has detergent properties.
Flushing oil reverses this optimisation - it has very enhanced detergent
properties and is just good enough as a lubricant not to damage the
engine at idle.

Basically you get 5 litres.  Drop the oil out of the car and change the
filter for a cheap and nasty one.  Put half the flushing oil in and
idle for 15 minutes.  Don't drive the car - flushing oil is not a
tremendous lubricant.  Dump the oil out and either empty the filter
or change it for a new PoS one.  Put in the other half of the flushing
oil and repeat.  Then do a 'proper' change to a high quality oil and
filter.  Some say the next filter change interval should be shortened
in case flushing dislodges particulates but I think fifteen minutes
at idle is enough.

Flushing oil looks like glycerine when it goes in and like tar when
it comes out, at least for the first change.  The second change
should be more brownish - if it's still black you may need to go
round again.  On an engine that has really been abused (few or
infrequent oil changes) it's a good idea to strip off and degrease
the breather system before starting.

For hydraulic lifter engines, you might like to add a spin after you
first dump the original oil.  Ground the coil and remove the plugs,
then spin the engine on the starter for fifteen seconds.  This isn't
long enough to harm the engine, and removing the plugs almost
eliminates crank loads anyway.  It _will_ cause some of the oil to
be pumped out of the lifters, and if you've ever changed hydraulic
lifters you'll know this is the worst oil on the car.

--
 Phil Payne
 http://www.isham-research.freeserve.co.uk/quattro
 Phone +44 7785 302803   Fax: +44 7785 309674