Strange oil consumption??? Or normal?

[KCJeep]

I have encountered an odd situation I hope you can shed light on. At last OC I introduced a mixture of Mobil products (all purchased on sale thanks to BITOG) and I've had some puzzling results.

The vehicle is a 2004 Chevy Venture 3.4 with 118k, it's always run on dino as far as I know (I'm not the original owner) but since I've had it the vehicle was mostly run on Castrol GTX 10w30. Normally the vehicle would use about 1/2 a quart of oil in 3000 miles. Last month I gave it Mobil which I've never used before. The mix consisted of 2 qts Mobil 1 High Mileage, 2 qts Mobil Super HM and 1/2 qt of Mobil Super full syn, all 10w30. To my surprise the vehicle consumed half a quart of oil in the first 500 miles! ( I always check oil frequently right after an oil change to make sure I didn't mess up, and the consumption was verified over multiple checks.) I then topped off with the last half qt of Mobil Super full syn. That was 750 miles ago and the vehicle doesn't appear to have used a drop since.

I don't get it. Is this simply caused by a brand switch? Is it the switch to a primarily synthetic mix from dino? Something else? Could the introduction of High Mileage additives have done it? I'm very curious as I've never seen anything like this before and I'd like to hear your thoughts.

Thanks!

 

[steve20]

why would you want to mix oils to that degree? I do not seethe point

 

[JoeWGauss]

I agree about excessive mixing of oils. Sure it won't do any major harm but it might reduce the effectiveness of the detergents in all of them, or alter consumption to some degree as well.

Optimally it is best to just go with one formula and weight if possible for the most predictable running.

I also figure it could be that there is higher detergency in the new stuff you were using.

Keep an eye on things and let us know how it goes in a couple more thousand miles.

 

[Artem]

I also think the extra cleaning additives in the High Mileage oils possibly cleaning up some stuff stuck on the piston rings, causing a bit of burn off in the process. Keep an eye on it and see if consumption stops/slows down.

I've also noted from personal experience that some oils will burn off a bit during the initial 500 miles or so and then consumption will stabilize. (perhaps its some additive in the new oil burning off, who knows)

 

[KCJeep]

The mix was an end result of a number of things, but being all Mobil 10w30's I figured it wouldn't matter much. It does run very well on it and consumption has apparently stopped for now. Peculiar and interesting I thought.

 

[KCJeep]

An update for posterity, now 2400 miles into the OCI and 1900 miles since I last added any top off and oil consumption still appears to be nada. Must have been something going on at first as it gulped down half a quart in the first 500 miles. The blend, change of oil type, I don't know.