Why does a car burn more oil after a brand swap??

[Lead Shoes]

Its a pretty straight forward question, but why do cars burn more oil on their first OCI with a different type of oil???

My car burnt about 1qt per 2k miles before, but after I switched to AFE from M1 5000, it burnt a quart over the first 1k.

 

[Lowcountry]

They don't.
Something else is going on.

 

[Artem]

I'd guess different formula chemistry of the new oil which burns off at a different rate then the previous oil.

If after an a few OCIs the consumption stops that is.

 

[TFB1]

Although it seems to be a popular belief that a engine will consume more oil after swapping brands, in 45 years of vehicle ownership, I can honestly say I've never seen a major change for the better or worse... Swapping grades to something thinner may increase consumption, as may a thicker oil slow down usage...

 

[HTSS_TR]

I never seen oil consumption increased with swapping brands or swapping dino syn. I didn't even see increased consumption when I used PP 5W20 instead of M1 0W40 the first time in E430 back in 2008.

 

[qdeezie]

Re-seating of piston rings. Not every time for every vehicle, however. Sometimes it happens, sometimes it doesn't.

 

[440Magnum]

I don't believe that a car will burn more right after a brand swap, then drop back to previous consumption levels. If it burns more when you first switch, its ALWAYS going to burn that brand/grade at a higher rate unless the formulation gets changed down the line somewhere.

 

[Lead Shoes]

So the consumption may curve for the better after a few thousand miles?

 

[hardcore302]

I change brands alot and haven't seen an increase or decrease..

 

[Big_Kat]

Originally Posted By: hardcore302
I change brands alot and haven't seen an increase or decrease..


same here, I use what is on sale and since my car takes 4.5qts, the last half qt. gets put in first.

 

[walk23]

You might try swapping to a High Milage Oil and see if that helps, or look into a PCV replacement as a cheap solve otherwise $$$$$$$

 

[jagger]

Just curious if you switch from conventional to syntheitc, will it: increase consumption, decrease consumption, or remain the same?

 

[Lead Shoes]

All of the maintenance is up to date, I did everything when I bought the car, but one thing that has me seriously wondering is the breather box, when I pulled out the old PCV valve it was black with what appeared to be oil and jammed closed, I am wondering if the breather box is clogged... It only burns oil at high rpm..

 

[friendly_jacek]

The effect is real. My 2GR-FE V6 in RAV4 burns no oil. But when I used one of the ZDDP additives, 0.5 qt oil was burned per OCI. I was quite shocked as it was on a relatively new engine. Then I used another ZDDP (SLOB), and no oil consumption. Now, I use no additives in this cars and no consumption.

BTW, the first additive was SAE50 oil based and produced no oil consumption in corolla.

 

[friendly_jacek]

Originally Posted By: Artem
I'd guess different formula chemistry of the new oil which burns off at a different rate then the previous oil.

If after an a few OCIs the consumption stops that is.


If so, why does it stop?

 

[friendly_jacek]

Originally Posted By: qdeezie
Re-seating of piston rings. Not every time for every vehicle, however. Sometimes it happens, sometimes it doesn't.


Why would rings reseat as they were set already? Increased initial wear with new oil or chemistry clash? I'm trying to understand that.

 

[dparm]

The new oil may have particularly strong cleansing properties, or the old oil may have caused deposits to form.

 

[friendly_jacek]

Originally Posted By: dparm
The new oil may have particularly strong cleansing properties, or the old oil may have caused deposits to form.


Don't ring deposits increase consumption?

 

[Lead Shoes]

I did drive it rather hard for about 500 miles it saw redline at nearly every stop up to 55mph, I also did an engine flush before this OCI, but for the first 500 miles it didn't burn anything.

 

[zrxkawboy]

I've personally seen it happen. Not sure why it does, though.