spiromax

A valid possibility...

I'm a Sentra owner, so I've spent a lot of time over at b15sentra.net. A lot of the problems that the Sentra owners are encountering sound very similar to the problems that we're encountering with our Maximas; for example, many of the QR25 guys have experienced MAF sensor failure, and they all keep ranting and raving about their "crappy QR25 MAFs" like the problem is somehow unique to the SE-R. What they don't realize is that other Nissans (like our Maximas) also experienced MAF sensor issues (probably because Nissan's parts-bin strategy uses the same parts or parts suppliers for multiple models).

Unusually high oil consumption rates are common for the QR25-powered Sentras from model year 2002 and 2003. It could simply be a coincidence that Maximas from model year 2002 and 2003 are experiencing the same problem, or this shared problem could be a result of similar parts used in the QR25 and the VQ35 in 2002 and 2003.

GBAUER

iTrader: (2)

Sounds like too much of a coincidence. They don't use the same rings, but some dip-siht engineer may have slightly changed material specs thinking they were doing a good thing and managed to f things up. When I worked as an engineer, I saw it done a couple of times to the equipment we were designing.

BlackBIRDVQ

iTrader: (15)

This reminds me of a time back in the mid 90s when Nissan came out to the dealership and took a Pathfinder and removed the tranny out of it- 140K miles and not a single oil leak. Engineers took the rear main seal off the engine block and went to the drawing board with it. They re-designed the rear main seal on purpose to make it leak. It almost sounds like the rings used on the VQ35 are similar to the QR25 ones- since those engines experience oil consumption like no other. Could it be Ghosn went cheap on engines now too ? Nissan is famous for having bullet proof engines but lately I'm not too proud of them. Personally I can't wait till the new V6 series comes out.

DaBoxSE

iTrader: (5)

I added oil and the rattle went away... I do get the rattle sometimes on startup. And also why is the oil really really really dirty (black) every time I do a change?

phobix

Ghosn's doctrine dubbed "NRP" (Nissan Revival Plan) is all about cost containment...I was reading some of the speeches given to employees on the global nissan news site and the speaker kept emphasizing the importance of "cutting costs" while maintaining quality. We all know that comprimises must be made in order to do this. How do you turn a near bankrupt company into turning a profit? By screwing the customer, we have all experienceed it, it has permeated to the dealer networks and to the products. Go see a nissan dealer about a problem, they will tell you they can't reproduce it or it is not covered under warranty. I am sure this is because Nissan corporate is much more stringent on warranty claims and the dealers are fearful of having to absorb the costs. Cost cuttitng is now one of Nissan's core values and IMO, due to this, nissan is going downhill and fast. Sure, they have some beautiful designs but that quality of yore which has drawn us into the brand has gone downhill.

MONTE 01&97 SE

iTrader: (1)

350 owners are complaining about the same thing:
http://www.my350z.com/forum/showthre...&highlight=oil

TheBigDu

iTrader: (1)

Man, this sucks. I thought the VQ35 was ranked in the seven best engines for the past few years. I'm not sure which organization or publication publishes these rankings, but you guys probably know what I'm talking about.

How could they miss something like this? I just changed my oil about 300 miles ago and I'm already at "L" on the dipstick.

njmodi

iTrader: (4)

that means you burnt 1qt in 300 miles... that's excessive by any stretch of the imagination... I'd be hounding NNA about that...

Are you sure you aren't leaking from the filter or somewhere else... thats a lot of oil to burn - I'm sure you'd notice it in the exhaust fumes - or its a leak..

TheBigDu

iTrader: (1)

I know, but I haven't looked into it yet. I'm going to move my car to flat ground and try again. I'm on a slight slope now, so I'm sure it's a little off (the reading) but not that far.

And of the two previous oil changes I've done since purchasing the car (got it used), oil only had to be added one of the times. I guess that doesn't make much sense, but what I'm saying is that I will take a look this weekend to see what the deal is. I'm sure if it's really that low, it's not just from burning.

I'll let ya know what happens.

GBAUER

iTrader: (2)

They sound about the same as us. As I stated before, the G35's have the same problem. Because it's on all three, I'd have to assume it's in the block, ie. rings. Notice how Nissan's solution is to replace the block, not the heads. That tells me they know it's a problem with the rings and instead of doing a proper fix, they are replacing the entire block complete with another set of POS rings! frustrating.

Daily Driver2k2

Seems like this problem is only happening with the 3.5ltr engines. Wonder if the 3.0 guys are having the same problem? But like i said before, i spoke to a Nissan tech and he said that it is normal for these engines to burn a "little" oil, he said that that is how the Vq3.5 was made. But who knows what the meaning "little" really means? It could be 1 qrt.,2 qrts, maybe even 3 depending on how far or little the consumer drives?

GBAUER

iTrader: (2)

Not a problem with the 3.0. Little, by Nissan's definition is less than 1 qt. per 1,000 miles. Doesn't really sound "little" to me, but....

chr0nos

iTrader: (1)

i dont think our engines "should" burn any oil. maybe 1/2 qt for the etire oil change interval (~5k miles or so). this seems to be a problem with a lot of people with the vq35 engine, but not everybody on .org has this problem. is there a definitive test we can run, to find out what's causing the oil consumption?
if it's a leak somewhere, it should pool below our cars, or show up in the engine bay somewhere...
if it's burning this much oil, our exhaust would smell funny...
oil doesn't just dissapear.

GBAUER

iTrader: (2)

I will do a compression test sometime in August and let you guys know where it's loosing compression. The oil is going through the exhaust, but you won't see it because the catalitic converter combusts the oil before it exits.

bvanlankvelt

Just wanted to make a comment on this math. Engines are designed for way more revolutions than that. You are suggesting that the engine only turns 3000 revolutions for each mile travelled (200 000 x 3000 = 6 million). RPM stands for revolutions per minute, not mile, and a car certainly does not average 1 mile per minute over its lifespan, considering all the idling and city driving done over the years, i.e. anything less than 60 mph. You can probably at least double that figure.

By the way, I have lurked on these boards for a long time and have gained much valuable info. I have a 2002 Titanium Edition 6MT with approx. 83K miles. My oil loss between 3500 mile changes is and always has been negligible. Have had car since new.

Thanks for the info guys, keep it up!

TheBigDu

iTrader: (1)

I hope this isn't directed at GBAUER. You're insulting his intelligence!

This is probably valid, but he does mostly highway driving, which is likely above 60 mph, so his average is probably not that far below 60.

Well, you either have a 2002 w/out the Titanium package, or you have a 2003 with the Titanium package, but you definitely don't have a 2002 with it.

bvanlankvelt

Actually I do have a 2002 Titanium Package. I am actually from Canada, though I messed up with my initial registration showing location.

Picked it up in March of 2002. Maybe the options and features were slightly different here than down there.

And I definitely wasn't insulting anyone's intelligence - just making a humorous comment. I'm sure Grabauer is very knowledgeable and was just making a very rough estimation without going into every detail - just a comment on accuracy.

GBAUER

iTrader: (2)

Actually A) I'm a fukctard. Really. I'm completely stupid.
B) I was only throwing out general numbers. Ya, most engines will actually see WAY more RPM's than that, but I was only trying to give an idea of scope here. You can think about how much the thing turns, but when you actually see the number, it's a lot more shocking.

GBAUER

iTrader: (2)

Here's some interesting info I got from Pat Goss, one of the Motorweek guys:

"George:

Appreciate the input. The cars I was referring to (the ones we service) are all high mileage. We don't get many cars that are still under warranty for anything other than oil changes. Those mostly go back to the dealer. Virtually all the cars I looked at on my database had well over 100,000 miles, seven were over 150,000 and six were over 200,000. Most are from Southern Maryland and accumulate over 50K per year. As to your testing you might want to consider another approach than compression testing which is usually worthless for diagnosing oil consumption problems.

Compression testing is for --- testing compression --- low compression means a rough running engine. Oil consumption is caused by one of three things: stuck or worn oil control rings, faulty valve seals, or bad valve guides. Because oil control rings have absolutely nothing to do with compression (there are two compression rings to control compression above the oil control rings) good compression tells nothing about oil consumption. Low compression also may have nothing to do with oil consumption.

We rely much more on spark plug examination using a magnifying glass. This will tell whether the oil is coming from the bottom of the engine (oil control rings) or the top (valve seals or guides). Over the last ten years (we keep relatively good records) we have found roughly 8,000 times more problems with valve seals than with piston rings. The one 3.5 we have experienced with oil consumption problems had bad valve seals.

No we do not overhaul engines as this is now considered a non-feasible in-shop operation. This is especially true of Japanese designed engines because of very sophisticated machining processes. we only install FACTORY REMANUFACTURED engines. These engines are done on a production line and all known defect areas are corrected with better parts or re-machining."

Now, anybody know how to test the valve seals? if it needs a valve job, it sounds a little more DIY than a complete rebuild. I'm starting to feel better, however, if it only needed a valve job, why would Nissan be replacing long blocks for warranty work? Any the mystery continues....

MiniRX7

Just to let you know, checked my oil, again reading at below the low mark.


In 8,000 kms... my car has read from FULL to LOW 3 times... I have topped up twice using 1L each time, plus my dealer has topped up in 3 occassions.

Somehting is definitely wrong here.

No blue smoke.

No power loss.

New gaskets installed..

TheBigDu

iTrader: (1)

Touche. Sorry to jump down your throat before, guess I was in a bad mood...and that it doesn't always pay to be a smart a*s.

99 SE-L

This is Crazy i just did an Oil change Mobil 1 Full Synthetic ,My VQ35 which has 94 k on it ate 2 1/2 Qts.

shabo99

Just my two cents here. But it seems like the common consensus is the rings. There may be some truth here;
http://forums.maxima.org/showthread.php?t=438738
Is there any corelation to busted/rusted precats to the oil leak. In other words, is this problem (oil leak) prevalent in those who do not have precats (Y-pipe).
Just a thought!

GBAUER

iTrader: (2)

Holy cow!!! I newbie with a brain who has obviously read other posts before deciding to chime in with stupid crap previously mentioned 50,000 times! Basically, I just want to give you a great big thanks from all of us with more than 50 posts!

In all seriousness, I'm starting to see the corrolation as well. This winter when I tear her down and fix her up, I'll let you guys know what I see in there.

kobalt

iTrader: (3)

As some of you know Im nearing 140k with virtually no oil consumption or leaks. Perhaps I got lucky but the 3.5 seems like a solid motor.

MiniRX7

Well my friend with 150K now has the rattling as well as massive oil consumption.
He called me and told me what happened, and its the SAME scenario with all the other members with VQ35DE.

Burning oil and rattling.

BewstAdd1ct

for leaking valve seals, you can look at the back of the valves, either with a borescope, or removing the IM...

99 SE-L

Nissan needs to do a recall, 2 1/2 Qts is redicolous

kobalt

iTrader: (3)

That's unfortunate. I get the rattle for a split second on occasion every other day or so - wasn't that linked to the chain tensioner? I hope I don't end up the same way...so far, so good.

eng92

iTrader: (3)

This is what I found in the 3.5 that I am swapping into my 98. It is out of an 02 max. The wrecker claimed it had 30K on it.


All cylinders were in the same condition.

The engine sat in my garage for about 4 months before I got around to doing a leakdown test. I had >40% pressure loss on several of the cylinders. Most of it was out the exhaust valves. Cylinder walls were mint, no scoring whatsoever.
I replaced all the rings, lapped the valves and now leakage is under 10% on all cylinders, which is very good for a cold engine.

I still have the exhaust manifolds, so I will take a look and see if there is any evidence of precat failure.

ABS

My strong recommendation, which is probably obvious anyhow, is not to install those pre-cats! The fact that you were able to identify the leak down occuring on the exhaust valves and there is obvious evidence of excessive oil stuck to those pistons tells me that you must have had oil leaking in past those exhaust valves and that those valves were more likely than not damaged by the pre-cats breaking down. If there is a silver lining to all this, it is that you found the primary problem was in the head and not the block . . .

Anyone know how much new heads cost from Nissan?

MiniRX7

My god.. I am so scared to check my oil levels on my new motor right now..

If it is leaking oil again, I am going to get rid of this maxima.... Or leave it at the dealership until NNA comes back for a full investigation or something and just take a retnal car.

I am still waiting for my Cattman Headers (GEN2)... If my precats are messed up the dealer will be responsible, as i EXPLICITLY told them to make sure the precats are in good shape. But they continued to install the new motor with broken precats. I have drieven several thousand kms on it, did an oil change at 800kms for break in.

If no oil loss.. then i hope the headers will fix this problem.

steven88

iTrader: (28)

this is an interesting thread...subscribing...

I have aftermarket headers on my car...haven't had problems with oil consumption...but i'm not sure if its directly related to the precats...I'm going to open my precats tomorrow and take pictures for you folks to view them

Maxim(a)SerjVQ

I've noticed alot of you have passed on the oil filter and break in procedure questions. I actually let the dealer do the changes for the first 20k, and on top of that, they were just using regular oil, not synthetics. Someone did mention that maybe the seals are of cheaper manufacture and require a more tender break-in process. I picked up my car with maybe 30mi on it, and tried to avoid running it past 3k rpm until roughly 1500mi were on the odo. Also when the oil starts getting older(+5,000mi), I've been more gentle on the throttle, and letting the engine temp gauge climb to the normal operating range before really running it. I know it may not be properly warmed up, but by then, I know that the oil has had enough time to get up into the heads. I have almost 70k on my 03 SE Ti and I would say that i -might- be burning a qt at around 6k. Speaking of which, after the first 20k, i started changing it myself. using Mobil1 5w-30, and using a Mobil oil filter on every change. I -HAVE- gotten the blue smoke out the exhaust before, but it was on a few occasions when i dumped the throttle on the engine when it was still cold. This could be entirely due to the fact that the engine isnt warmed up, at least in my case. don't forget that the cats and precats are designed to operate properly when hot. the Wankel 13b had a major issue with its exhaust because the temp was too hot, but the engine had to have more than one cat to meet emissions, which would fry and send shrapnel into the second cat and effectively killing the power output. Sorry for getting off topic, but all this oil burning may very well be entirely attributed to improper break-in on cost-cutter seals combined with the best VVT system you can put on an engine. with the engine running in an advanced timing state on a cold engine could just be sucking oil in past an unexpanded seal into the exhaust and clogging or frying up the precat.

If that's not a reasonable explanation, and you run your engine for long; it may be due to improper break-in that's permanently caused a seal that wont close up properly when it warms up. the seal may be 'bad' because it was abused, not necessarily because they suck.

I'm just running down a theoretical path, because i really dont think the VQ series would have kept winning a Ward's Ten Best for the 11th straight year with the Honda 3.2L (VTEC and 270hp; more efficient than the VQ on paper) breathing down it's neck as well as the Caddy 3.6L VVT (which imo is a -very- good engine). Feel free to yell and scream at me for my bunk theory, but i have raced for several years and know the importance of a GOOD break-in period.

BlackBIRDVQ

iTrader: (15)

I only have 130K miles on my 3.0L and I did NOT break in my engine, unless bouncing off the rev limiter in 1st gear while leaving the dealership- and barking 2nd gear counts ! I don't have any oil burning issues, and I abuse my car VERY bad- imagine I am on my 9th set of tires :P

There really isn't a break in period on many of the new cars. I know working for Acura as a tech we don't have a specific break in period. And I know I beat the bejesus out of the new car when driving them around durring PDI. Those same cars I PDI 4 years ago, still come in for normal service. No to burst anyones bubble, but Hondas J32C1 motor in the TL/CL Type S with 260HP is more reliable than the award wining VQ35. Honda has issues on injectors- sometimes but rarely on this motor. They don't burn a drop of oil, don't leak a drop of oil, and they sing all the way to 7K RPM all day long- as long as the POS 5AT tranny hold up.

U want a reliable Maxima, U stick with a 3.0L, I'm sorry but its true.

ABS

Actually, many of us did follow a rigorous break in process. I for one changed my oil to Mobil 1 at 500 miles and then completed 3 oil changes by 5000 miles. I also babied the engine for the first 1000 miles by keeping it at low RPM's to ensure the piston rings had a chance to seat. My engine ran like it was new and burned absolutely no oil up to around 78000 miles at which point all hell broke loose and now I am burning a quart every 1000 miles.

I am certain that I did nothing "wrong" to cause this to happen as I always changed my Mobil 1 on a regular (and frequent) basis. I also only used Mobil 1 or Nissan oil filters. Let me also add that I always refused to use any type of aftermarket air filter (I stuck to the OEM Nissan paper filter) to avoid any risk of the engine ingesting dirt from a more porous filter . . .

The fact is that at some point the ceramic core of the pre-cats just start to break down rapidly. When this will begin and what causes it to occur is not known to me at this time. However, when it happens and the engine ingests a crap load of ceramic dust, it is just like pumping millions of sand granules straight up the intake of the engine. Not much could be worse than that.

Nissan is caught in a catch 22. The converters can not be removed altogether and replaced by a straight pipe since emissions would suffer. Replacement converters are VERY expensive and Goshn would never agree to replacing them due to the cost. Besides, most of us are having problems AFTER the Nissan drive train warranty is up. Now it is our issue to solve and not Nissan's. Just wait until the general public hears about this - the value of every Nissan or Infinity with the 3.5VQ is going to plummet.

Kevon1

iTrader: (12)

Amen to that. This is my third 3.0 Maxima . Never a engine issue with any of them. Never burned oil. Great engine that I am not quite sure Nissan made better.

GBAUER

iTrader: (2)

Thanks for the pics! Mine has 138k on it, but I've only used synthetic oil. I hope it's only the valves leaking and not scored cylinder walls. regardless, I'm looking forward to playing with it.

ABS

Anyone know how I can test to see if the problem is just in the heads, just the block or the heads and block?

Thanks!

eng92

iTrader: (3)

Without doing a partial teardown of the engine (ie remove the heads), I believe a leakdown test is the only thing you can do. It will only tell you where the leaks are (intake/exhaust valve or rings) and not what caused them.