Jim said:
From my understanding, the biggest risk of switching from a conventional oil
to a full synthetic on an "older" car, is that where standard oils cause the
seals to swell slightly, synthetic oils do not. This results in the
potential for the seals to "unswell" and start to leak. I really wouldn't be
Hi,
I'm not sure, but I think the problems you've mentioned are ideas held
over from the early days of synthetics. All of them for sale today have
been modified many times over the years, as have seal materials, to the
point I don't think there's a problem.
IF a switch to synthetics today results in increased oil leakage, I
think it's a function more of the synthetic's superior cleaning
qualities simply "opening up" areas that were sealed more by varnish and
goo rather than the actual seals.
I switched my Subie to Mobil 1 for a "test" at around 250k miles--no
increased leakage was noted. But it was already using about 1 qt/1500
miles on dino oil, and the consumption rate stayed the same, so the
economics of the situation said "use dino!" OTOH, I switched my Camry
('92 V-6, with the "usual" tiny leaks that engine's noted for) from dino
oil to synthetic blend at 225k miles: the leaks are hardly noticeable
now, and consumption went from approx 1 qt/2500 miles on dino to approx
1 qt/5000 miles on the blend. So I wouldn't worry about leaks!
Rick