Excess Oil Consumption with VQ35 engine?

[Martinjmpr]

Does anyone know if the VQ35 engine has been known to have oil consumption/burning issues?

Back in January I noticed my oil was low by over a quart. Added oil and brought it up to showing full on the dipstick. This would have been about 4 - 5 weeks ago.

About a week ago, the Pathy threw a CEL. I don't have a Scangauge or Ultragauge (yet) so I ignored it. Previous owner told me sometimes the CEL would go on with no change in performance, I figured it was a sensor or something, no big deal.

Last night, with the low fuel light on I decided to fill it with gas. As usual, I checked the oil (after it had been sitting on a level surface, engine shut off, for maybe 5 minutes.) Dip stick was once again BONE DRY.

So I drove to Wally World and bought 3 quarts of 5w30. Put in the first quart - still no oil on the dipstick. Put in the 2nd quart, now it was showing full.

Closed everything up (the 3rd quart is still sitting in the back of my Pathy.) Went to start - lo and behold, the CEL was off!

So, I'm asking here: Have there been any reports of excessive oil consumption with the 3.5? My old Montero with the 3.0 V6 would burn about 1 quart of oil every 1,000 miles but it also had noticeable blue smoke coming out of the exhaust.

I park in a driveway and if I was leaking oil anywhere, I would know it (actually I would catch hell from my wife because we just moved into a new-to-us home.) If it's not leaking, it must be burning, yes? I mean, what else could account for the oil loss? Keep in mind that the truck was full of oil as recently as January and by the end of February it was down by 2 quarts!

I should point out that through all of this, every aspect of performance, power, fuel economy, etc, has been completely unchanged. MPG in mixed city and urban highway driving remains around 17 - 17.5. That's running regular 85 octane E10. I did about 3 tanks of 91 octane with absolutely no difference in performance or MPG so I went back to regular.

What could excess oil consumption be a sign of? Again I have to point out, it's not "smoking" like a vehicle with bad piston rings would likely do (I've had a vehicle that did that, but it had over 200,000 miles on it, too!)

Thanks in advance!

[disallow]

i'd be looking for a leak. Your CEL probably has nothing to do with the oil level. But there is no way to tell if you don't get the actual code and tell us what it is.

[smj999smj]

There have been some known issues with oil consumption on the VQ35DE's in both the Pathfinder and Maxima. Originally, people were replacing the PCV valve and/or right bank valve cover (in which is the PCV baffle) and some claimed this fixed their issues. The worse, and more prominent issue, has been blamed on poor ring sealing. The VQ35DE cylinder bores are manufactured with a very slight taper to them. Supposedly, the lower rings on the piston wouldn't seal again the bores as well as they should and resulted in blow-by. Nissan came out with a correction to this problem with a different ring set, but, of course, the problem is that there is a lot of work and expense in re-ringing an engine.

[Martinjmpr]

There have been some known issues with oil consumption on the VQ35DE's in both the Pathfinder and Maxima. Originally, people were replacing the PCV valve and/or right bank valve cover (in which is the PCV baffle) and some claimed this fixed their issues. The worse, and more prominent issue, has been blamed on poor ring sealing. The VQ35DE cylinder bores are manufactured with a very slight taper to them. Supposedly, the lower rings on the piston wouldn't seal again the bores as well as they should and resulted in blow-by. Nissan came out with a correction to this problem with a different ring set, but, of course, the problem is that there is a lot of work and expense in re-ringing an engine.

Yeah, right after I posted that I did some Googling and lo and behold, I found a whole bunch on the VQ35 excess oil consumption issue.

My concern is not the oil itself. Oil is cheap, relatively speaking, so if burning oil is all that is going on, I can live with that.

My concern is whether the excess oil consumption indicates that my engine is in a downward spiral that will ultimately result in failure, and if so, how long I can expect it to last.

There seem to be mixed reports on that, some say the oil consumption is a death sentence, other say it's NBD, just watch the oil level and top off as necessary.

The Pathy is my DD and "city" vehicle, so it's not like it's my only car and it's not like I'm heavily invested in it emotionally.

I like it, and plan on keeping it at least for now. But if it starts to show signs of other issues, I'll probably unload it and find something different.

[smj999smj]

The biggest concern is the restriction of the catalytic converters, especially the upstream converters. The oil will gradually clog the front converters, causing a loss in power and creating an expensive repair. The bigger issue exists for people that do not check their oil and eventually run the engine on little oil, creating wear to the other internal engine parts. How long will it last in this state? No one can really say. It's no different that running an engine with a bearing knock or driving on a noisy wheel bearing hub. Eventually, the problem will come to a head and need to be addressed.