Since switching to Catrol Syntec 10-30, I seem to be losing oil at about a
1/2 quart every two weeks. I know about average oil consumption but I never
lost oil with dyno or syntec blend. I have no external leaks nor any smell
of buring oil. Coolant looks good, no change in level and no milkshakes.
BTW, this is in a '00 OBW 2.5 auto w/ 83K. I do about 400 miles/week in
mixed driving.
Is this oil so thin and slick that I'm burning through the valve guides?
I'd hate to swtich back to dyno or blends expecially with winter coming here
in MA.

--
John

"John" <noone (AT) here (DOT) com> writes:

That's high oild consumption for sure. Have a look at what's coming
out the tailpipe. If it's not leaving hte head gasket to coolant, if
it's not leaking out onto the engine or leaving a spot where you park,
that I believe only leaves the rings and blowby.

Now what's weird is that it just started with the switch to a
different oil (assumably after an oil change). I'm skeptical of the
thought that a 10w30 is going to magically slip by anything after not
being an issue with the last oil. Sure you're not losing it from the
filter fitting or the drainplug? If not, I'd redo the oild change
and go back to whatever you were usin!

Best Regards,
--
Todd H.
2001 Legacy Outback Wagon, 2.5L H-4
Chicago, Illinois USA

John wrote:
Well a '00 doesn't seem old enough, but I've heard that on older cars
that its best not to switch from dino to synthetics because the
synthetics have a tendency to clean out oil deposits. Seems that
sometimes these old deposits are blocking places where the oil could
leak. Switching to a synthetic removes the blockage and now you have an
oil leak.

I have heard from others on the NAIOC site that higher than normal oil
consumption sometimes occurs with the first oil change to Synthetic.
The consumption usually returns to normal after the second oil change.
I would follow your normal oil change interval and see if that is the
case when you change oil the next go-a-round. Ed

John wrote:

Hi,

I suppose that's a possibility... if I do the math right, you're looking
at about 1 qt/1600 miles or so? At that rate, it COULD be slipping past
the valve seals and being slurped thru the guides w/o visible smoke
(have someone watch the tailpipe from behind when you start up cold,
then drive around in mixed driving: small puffs of bluish smoke upon
acceleration from a stop are one sign of valve guide problems.) If your
cat's in good shape, it can mask a fair amount of oil consumption smoke.

However, I wouldn't give up too quickly. At the mileage you've noted,
it's quite possible your engine's got some fair deposits on the rings as
well as valves. What I've seen with SOME engines that were switched to
synthetic was that the oil consumption INCREASED for a while as the
synthetic dissolved some of the deposits, creating "leakage" points,
particularly if the rings were sticky, then the consumption DECREASED as
the engine became cleaner and things started to seal up better.
Essentially it's the "oil leak" theory w/ gaskets and seals, only
internally. Watch the color of your oil: is it getting darker faster
than it did w/ dino or syn-blend oils? If so, it may be working rather
well at cleaning out "goo."

Another odd possibility is that some junk has been broken loose as the
synthetic dissolves stuff and been sucked up into the PCV valve. If
clogged, this can hurt oil consumption, so it's one more thing to look
at.

To be fair to your engine, I'd probably consider 5000 miles or so a
"reasonable" test of the "internal cleansing" theory.

Rick

Thanks for all the responses, I'll keep using the syntec at the next change
and monitor how it goes from there. The oil did go darker than I had
expected but I also don't have any blue smoke or clogged PCV


--
John

John wrote:

Synth oil WILL be darker - most especially after switching from dino in
older vehicles. Evidently, its due to synths ability to better keep
varnish in solution. Better to drain it out I guess - though I'm not
convinced the varnish harms anything.

Carl


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