Hey gang,

I haven't written on this particular section of NICO before. There are a few things on the VQ Im sure you may want to know. If you already do, then disregard this information, but this is good information.

1) If your VQ is losing/burning oil, it is NOT because of the viscosity. The problem lies in the taper of the cylander bore. All VQ engines have a tappered bore, and on some, it is excessive, to the point where the secondary rings and oil control rings are not making full contact with the cylander walls. Durring heavy deceleration, or high rpm deceleration, the vaccum in the cylander draws oil past these rings. In a situation where you are losing 1qt every 1000 miles, you can be sure to find secondary rings that show minimal signs of wear. (since they are not in contact with the walls, why would they wear?)

2) Got a buzzing/whinning noise when you start the engine? Does it continue durring driving? While a rattling noise durring crank up is more than likely due to low oil, a buzzing or whinning noise while driving MAY BE CAUSED by worn secondary timing chain tensioners. What happens is the plastic guide on the tensioner wears down to the tensioner piston. The chain then rides this piston instead of the guide, causing a whinning noise. In some cases, a bad alternator clutch (yes, the new alternators have clutches) can cause this. In the situation that your tensioners are to blame, expect to spend from $1000 to $1500 to have them replaced and should include new upper (secondary) timing chains.

3) Yet another buzzing, rattling or whinning noise. If you own a Quest van, Maxima, Altima 3.5 and some Z/G/FX vehicles, and get a loud buzzing noise on start up, or rattle, this may be due to the main chain guide breaking. The main guide recieves pressure from the main timing chain tensioner. At the top of this guide, where the chain exits on its way to bank 1 (Left hand from front), the guide wears and eventually breaks at that mounting point. The plastic on the guide then drops about 1/2 inch to reveal some of the metal bracket of the guide. This is the sawing, buzzing rattling noise you hear. Again, it may just be low oil, but if that doesnt fix it, this is probably what you have.

4) VQ wont start, wont spin over or even act like its alive. In some cases, I have found that one of the connectors going into the IPDM board are loose. This is the black box with fuses in it near the alternator on FWD vehicles and near the battery on RWD vehicles. Before you freak out, and after you have tried a jump box, try pressing all the connections into the IPDM to seat them. If it still doesnt start, check to make sure your security light is not on when you turn the key. If your key is turned to start, but the light is on, you have a NATS malfunction, and you should have your car towed to the dealership.

5) Rattling, grinding noise at idle from RWD 6 speed transmissions. GET USED TO IT. They all do it. May not be as loud on some, but they do. My 6 speed is loud, and it is from a 2006 350Z which had less than 6K miles on it when it was removed. I have rebuilt several of these transmissions and see no signs of wear that would be the direct cause of this sound.

I guess thats all I can think of at this moment that could be very beneficial. If your wondering how I came across this information, its from experience. I have been working for Infiniti/Nissan for almost 10 years now. I am a lead technician at a Nissan dealership and have inspected/rebuilt, modified my fare share of VQ engines. Want to see something I've built for proof? Check out my thread on here

zerothread?id=207033

I hope this information helps everyone!!!! Feel free to ask questions, but I will say, Im pretty busy most of the time, so it might take a bit for me to get back to you.

Wow good info! About the oil loss issue, any suggestions for correcting / minimizing loss without a rebuild? And is the taper there for a reason?

Thank you for all that info. Had one of those VQ35DE revup 298hp engines just replaced due to oil consumption. What you say about the cylinder walls I've heard as well. Another was something about the valve guide seals with the high vacuum pull under certain conditions.

Always scratched my head and still do as to why only some 298hp(G35's)/300hp(350Z's) experienced this issue while many haven't with their oem factory VQ's still in service. Apparently the second revised replacement has fixed these known issues. Crossing fingers. Any insight to what they've done to these revised VQ's being used as replacements?

Whining sound question: I have a whining sound that is from my 6mt gearbox. It sounds like a faint super charger whine. Has done this since new and is slowly becoming louder. Know it can't be my timing chain and related parts being, I just got a new VQ35DE long-block. Any thoughts about that noise from gearbox? Syncros are fine I assume. No shifting issues in any gear.Thanks.

Where exactly is the transmission noise coming from? Throw-out bearing? Anything out of balance part? Anyway to improve it?

Your whinning noise is more than likely normal. The 6mt makes alot of horrible noises, due to the large gears and bearing (bigger than the old stuff!). If its whinning at light acceleration, then what gear is it doing this in. If it is all, then it could be an input/output bearing. I wouldnt be too worried as alot of them make noise, but if it wasnt there before, and is getting louder, then you might have something that needs to be corrected soon.

The taper is there for a reason. The update to the engines was a different set of piston rings. The secondary rings origionally had insufficient tension against the cylander walls. All new engines and remans are comming with the updated piston rings. As far as minimizing the oil loss.....best thing I can tell you is to just keep an eye on it. If you have it, it's like cancer, it will eventually get worse. Sorry

SpecDRacing wrote:Your whinning noise is more than likely normal. The 6mt makes alot of horrible noises, due to the large gears and bearing (bigger than the old stuff!). If its whinning at light acceleration, then what gear is it doing this in. If it is all, then it could be an input/output bearing. I wouldnt be too worried as alot of them make noise, but if it wasnt there before, and is getting louder, then you might have something that needs to be corrected soon.

1st; 2nd; 3rd whining, sometimes 4th and in all rpm's. 5th/6th apparently none or road noise/aftermarket exhaust drowns it out in those gears/mph speed. Had noise since new as mentioned, but is becoming more apparent now. Been using 100% Synth 75w-90 API GL-4 with only ~15K service on it.

Heard some of these gearboxes going South on syncro issues, but not in/output bearings. Have warranty so will address issue if it continues to worsen.

Thanks for your insight and reply.

I've read that people have to mix off shelf gear oil to get weight in Nissan factory spec.

Maybe your issue is also related to oil?

BTW, what kind of lube should I use for throw out bearing spacer?

Soravia wrote:I've read that people have to mix off shelf gear oil to get weight in Nissan factory spec.

Maybe your issue is also related to oil?

BTW, what kind of lube should I use for throw out bearing spacer?

Possibility and an interesting thought, thanks. Though shop service manual states to use: (MTF) HQ Multi 75w-85 or API GL-4, Viscosity SAE 75w-85 or 75w-90.

I'm using Amsoil's SAE 75w-90 API GL-4. Suppose if whining doesn't get any louder, I'm okay. Can't help you on what lube to use with throw-out bearing.

I also received the revised engine. Previous engine not only burned oil, but seemed easily floored when I stepped hard on the pedal. Secondly, that engine seemed to hate working cooperatively with the trasnmission.

Revised VQ engine is stronger and seems happy to be mated to my current transmission noise.

My transmission, after changing my 6MT gear fluids first to synthetic brands for 2 weeks, I asked the dealership to switch back to genuine Nissan transmission fluids as stated in the manual. I have a whinning/whistling noise like a supercharger or turbo charger, but it is getting more quite as the oil ages in the trasnmission. When I first changed the oil, it was quite loud and noticeable. But the whining occured at between 3000 - 4000 RPM. But now, the noise is almost gone---only hear it occassionally.

While I think these cars will always make lots of noise, I am of the beleif that the way a person drives their car has a lot to do with the intensity and frequency of the noises heard. My car---engine and transmission, seems to be well behaved, noiseless, and very obedient, after a very intense and spirited session of driving. Car's transmission is noisiest upon start up, but quickly quitens as it warms up.

If you have to worry about all the noises in the 6MT, it will drive you mad. Just enjoy driving the car and stop worrying about all the many strange and confounding noises on the car. Even Nissan Engineers can't even tell you what those nosies really mean or where they are coming from.

Oh, another thing, the G-35 Coupe seems to hate being left to sit for many days at a time. Those babaying their cars or letting it to sit, are going to be shell shocked when they realize how non-compliant and troublesome the car can abe when it is not driven aggressively or continuously.

How expensive is it to repair those synchros anyway? How much for parts? Is it something I could do myself with basic tools?

[quote="SpecDRacing"]Hey gang,

[quote] I haven't written on this particular section of NICO before. There are a few things on the VQ Im sure you may want to know. If you already do, then disregard this information, but this is good information.

1) If your VQ is losing/burning oil, it is NOT because of the viscosity. The problem lies in the taper of the cylander bore. All VQ engines have a tappered bore, and on some, it is excessive, to the point where the secondary rings and oil control rings are not making full contact with the cylander walls. Durring heavy deceleration, or high rpm deceleration, the vaccum in the cylander draws oil past these rings. In a situation where you are losing 1qt every 1000 miles, you can be sure to find secondary rings that show minimal signs of wear. (since they are not in contact with the walls, why would they wear[[/color


I saw this posting when I googled "DISPLAY CYLINDER WALLS OF VQ35DE ENGINE"
Your response was unique.
Now that you have been around those engines for more than 14 years~!, what do you know of the engine replacements that went back to the dealer with same problem !!!!!
Any news from the time you wrote this responce?
Any ideas why between zero to 25,000 there was no oil consumption, but after that, "the flood gates opened"?!?!
Please let me know because the dealers are tricking me with this oil consumption issue and Technical bulletins.

Items 2 and 3 got me.
I took it apart myself and now i have to replace the right intake sproket becasue the guide dowel somehow got compressed when try to install the rear secondary tensioner shoe.
Do you think this is the reason why i lost oil pressure?
Nissans design on the plastic guides are dumb. I feel they should recall it but i know that wont happen.


2) Got a buzzing/whinning noise when you start the engine? Does it continue durring driving? While a rattling noise durring crank up is more than likely due to low oil, a buzzing or whinning noise while driving MAY BE CAUSED by worn secondary timing chain tensioners. What happens is the plastic guide on the tensioner wears down to the tensioner piston. The chain then rides this piston instead of the guide, causing a whinning noise. In some cases, a bad alternator clutch (yes, the new alternators have clutches) can cause this. In the situation that your tensioners are to blame, expect to spend from $1000 to $1500 to have them replaced and should include new upper (secondary) timing chains.

3) Yet another buzzing, rattling or whinning noise. If you own a Quest van, Maxima, Altima 3.5 and some Z/G/FX vehicles, and get a loud buzzing noise on start up, or rattle, this may be due to the main chain guide breaking. The main guide recieves pressure from the main timing chain tensioner. At the top of this guide, where the chain exits on its way to bank 1 (Left hand from front), the guide wears and eventually breaks at that mounting point. The plastic on the guide then drops about 1/2 inch to reveal some of the metal bracket of the guide. This is the sawing, buzzing rattling noise you hear. Again, it may just be low oil, but if that doesnt fix it, this is probably what you have. [/quote]

Anyone know if the new tensioner shoes and/or new 2ND tensioner assemblies designed for the VQ35DE in 2004-2009 can those be used on the VQ30DE(K). e.g. on a 2000-2001 Nissan Maxima (A33). Just for others, what about on the Max's earlier VQ35DE in model years 2001-2003. (I think the early model VQ35DE had the same or extremely similar 2ND tensioners as the VQ30DE in '00,'01 Max). Then Nissan changed the tensioner design in 2004 so that the shoe could be replaced without replacing the entire assembly. The entire design appears frankly to be a "perhaps THE" weakspot on the engine, and Nissan still hasn't done anything to really address this. Surprising. I'm not surprised that they pretend the issue is minor so as not to get sued, but I am surprised that in 10 years of engine issue on this, they have not really designed in a real fix.