06 6mt here. prod date 10-2005.
Worst to date was 1qt/1200mi between my 3750mi and 7500mi interval and toward the end of that interval. During new to 3750 was only one quart usage (figured that was normal break-in usaged...no concern). Now in middle of 7500-11250 interval at almost 9000mi and only 1/2 to 2/3 qt down. Seems to be getting somewhat better and driving habits have not changed. But Dealer used Castrol 5-30 dino as opposed to, I'm guessing, Nissan's oil prior... being prior, I have nothing written saying what brand.
Here's my .10 worth on my readings-theories/logical-possible cause/service tech statements at Dealer:
As I have suspected for some time, this issue seems to be mostly pointed to the Revup VQ (05-06 6mt's). This poll so far is supporting that theory.
Because this apparently is a random issue with the VQ's, my logic tells me there may a part supplier QC problem in the assembly/production line on these VQ's and possibly Nissan is using more than one vendor for these same parts. By parts, I'm guessing the possibility of oil control rings or the molybdenum coated pistons, possibly.
If this is true, then it would explain why some VQ's have this problem while others (the lucky ones) do not.
And I'm still pointing my finger at the 05-06 Revup's as this poll and some other posts support. Plus my theory is the 298hp VQ design has gone beyond it's limit, perhaps.
Look at the specs and re-design of their new VQ35HR. Yeah re-designed for higher rpm, more HP, but also designed for less stress on the cylinder walls and piston rings. Hmmmm.
Just found that the VQ35DE is also manufactured in Tennessee.
Scroll to the VQ35DE description. Here's a short quote: 'The VQ35DE is built in Iwaki, Japan and Decherd, TN.'
Click on the Decherd, TN hyper link and it takes you to a page about the location then there's a link to the Nissan Plant.
Here's that link to save you time in finding it:
quick copy/paste from that link:
Components produced in Decherd: Engines for every Nissan and Inifiniti vehicle manufactured in the United States
2.5 liter, 4 cylinder
3.5 liter, 6 cylinder
4.0 liter 6 cylinder
5.6 liter, 8 cylinder
Wonder if we're on to something here????? Hmmmm.
Now as far as the break-in procedures, I have read ppl who have followed that and ppl who haven't. Too much variance whether that is a factor, so IMO, I discount that theory as being a cause for this excessive oil consumption.
Read about what oil you use has an effect. Some say they've seen improvements, but not dramatic. So, again IMO, inconclusive to the cause. I personally haven't switched to synth. I use what Nissan recommends or should I say what the dealer uses, (which I assume is approved by Nissan for use in their VQ's)
Almost done ppl.....
My dealer service guy said these VQ's have high vacuum pull. Especially, don't quote me on the exact rpm, something over 3000-35000rpm's on up. This can pull oil through your PCV valve, up your hose and into your intake plenum, which then exists through the combustion chamber. As he said to me, your driving habits have an effect on this.
I believe this is true to a point. But then why some ppl drive like they stole it everyday and have no oil consumption issues...
There's a post here about an oil catch can mod. It captures the oil before entering the plenum. Some ppl who've done this mod see a lot oil in their catch can, while others see very little.
Still doesn't explain why some VQ's are worse than others, but does prove the high vacuum theory and that's another way of how the oil is being consumed.
Some of you ppl with spacers and MREV's probably can confirm this when you pulled your OEM plenum and saw what was inside. Someone posted a pix here too and it had quite a bit of oil in there.
So, last thing my service guy told me in regards to the vacuum thing. When the VQ loosens up, it won't pull as much vacuum as new and the oil being consumed through the intake runners will decrease over time, hence, oil consumption will decrease.
I somewhat discount this explanation due to some ppl who drive theirs mellow all the time, stays in the mid low rpm range, but still have this oil consumption issue. But on the other hand, mine is getting a little better over time as the miles are clicking away on my odo.
So it is quite confusing.
Who knows why....haha...Nissan doesn't even know why (they probably do, but not disclosing publicly, that would ruin their WARD's 10 best engine awards they have gotten every year since 2002 and is the only engine to be on that list every year).
Final thought and sorry for the novel, but been doing a lot of reading/searching about this issue
I find it very sad that Nissan has set forth 1qt/1000mi to be an acceptable usage threshold for these VQ's even when they're new and will only do something about warranty wise it if exceeds that 1qt/1000mi usage........so sad.
I am intriqued and has me wondering about the US plant that produces these VQ's also. I never knew that until now. I wonder..................
It'd be nice if Nissan/Infiniti would step up to the plate and tell us why this is happening. They've dropped the ball somewhere on these VQ's.
Thanks for listening and hope someone gets to the bottom of this.