Synth changeover

[Al Powell]

<mark.e.woodland at gsk.com> asked:

After following the recent thread on bulk synthetics, I was ready to take
the plunge on Max, the '87 5KTQ w / 268k (all dino miles)., as I'm still
adding 1000 miles a week, and the oil change intervals have stretched.
On doing some local inquiry I was told the horror story of a guy that
switched over on his S**b Turbo, only to have the detergent action of the
synth loosen up some deposit or another, and sieze the turbo. Scared me
enough to continue with the dino, but I am curious to know if anyone else
has any similar horrors to share.
What would be the suggested time or mileage to change the oil filter after
the transition to synth, assuming that the synth had just pulled a lot of
deposits out of the engine?
Thanks,
Mark

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Mark, I honestly would not let this dissuade me from changing over - nor has
it in the past. I find it amusing that one lister emailed me this week
telling me that all oils keep engines nice and clean, and your comments
comes up later. Yes, all modern oils DO keep engines nice and clean if
they're changed often, etc. However, "stuff happens".  I recall clearly that
when I put a turbo on my 280ZX (original one was killed by the first owner)
the directions clearly stated that the warranty was void if the oil feed
line to the turbo was not replaced at the same time as the turbo. Yes
indeed, oil deposits can form, and they can break loose and plug oil lines,
oil passages, etc.

Synth oils ARE more detergent than most (if not all - had to throw in a
qualifier) conventional oils. They also tend to wick better and can
therefore work through loose gaskets. As a result, they not only have the
potential to loosen deposits in the engine, they also can create slow leaks
where none previously existed. However, if they do leak, it means there was
a problem in the first place, not that they created the problem.

The best way to prevent floating junk is to clean the engine as well as
possible. If you've run a high detergent oil and changed it often, you
should be OK anyway!! My recommendation in changing to synth is to get a can
of engine cleaner (Gunk is readily available, Amsoil and others make
comparable stuff) and run it through the engine as per directions. Drop the
motor oil and filter and install synth. Make the first oil and filter change
no more than 3K miles later, then re-fill and re-filter and drive it the way
you're going to drive it.

Enjoy.
************************************
Al Powell
apowell at gocougs.wsu.edu
1958 Fiat 1200 Transformabile Spyder
1983 Datsun 280ZX Turbo
1993 Audi 90Q
1997 Chebby Blazer
1999 Chebby Blazer
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