Where's my oil going?

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.
Reply to
John
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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
Reply to
Todd H.

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.

Reply to
Ed

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

Reply to
Edward Hayes

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

Reply to
Rick Courtright

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

Reply to
John

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

Reply to
Carl 1 Lucky Texan

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