Engine Noise Coming From Underneath The Lower Intake Manifold Collector

[NISMO-61]

Hi all,

I need mechanical advice regarding a bloody annoying noise coming from the intake manifold area. Actually the sound (which is kind of ticking as it goes like "tick tick tick tick" after 1000rpm. When it goes over 2000rpm, you don't hear it. When I removed the engine cover(the plastic one) it is %100 obvious that the noise is coming from underneath the intake manifold assembly.

A few weeks ago, I removed the whole manifold thing to see if there was something wrong with it, but it was totally ok as there was no part in it that would make that noise.

whatever sits underneath the manifold is possibly causing the noise.

I don't have much mechanical information about the engine, therefore I need help to figure out what might be the problem so that I can take it from there.

Extra info; when the engine is cold, it doesn't do that noise. when it's warm, then the action starts. Engine performance is as usual. When the car is in idle, there is no sound as well.

Any help would be highly appreciated.

By the way , would you be able to recommend any mechanic in the northern suburbs of Melbourne who knows about this cars?

Regards and thanks in advance. Your help is highly appreciated.

[NISMO-61]

just to clarify the area not to cause any confusion; the noise comes underneath the INTAKE MANIFOLD COLLECTOR which is sitting on top of the engine.

[Deep Dish V35]

for mechanical info see here

index

http://psedog.com/cars/fsm/g35/coupe/2004/idx.pdf'>http://psedog.com/cars/fsm/g35/coupe/2004/idx.pdf

then relate section by letters and page number

http://psedog.com/cars/fsm/g35/coupe/2004/

[pv35gt8]

Are you sure its not coming from the the intake manifold collector, where the injectors are sitting.

[Deep Dish V35]

i was thinking injector, valve, maybe a cam lobe... most likely an injector

wont be an inlet gasket because it would hiss, could possibly be an exhaust manifold gasket leak

you could try using a mechanics stethoscope to have a clearer listen...

the pdf's above should help you see what is under the area of the sound

[NISMO-61]

i was thinking injector, valve, maybe a cam lobe... most likely an injector

wont be an inlet gasket because it would hiss, could possibly be an exhaust manifold gasket leak

you could try using a mechanics stethoscope to have a clearer listen...

the pdf's above should help you see what is under the area of the sound

Do you think an injector would make such a noise. I'm %100 sure that the noise is coming from whatever is underneath the intake manifold collector. well the injectors are right there anyway. We removed the intake manifold collector before thinking that it might be causing the issue, but no. We removed the upper and lover plenum.

The thing is when the car speeds up, you don't hear it. maybe because of the road noise,

It's more obvious when you stop and then accelerate to move, then you hear the sound.

If it is the injector, would that be normal; making noise while accelerating, not making the noise over 2500rpm.

Cheers guys.

[pv35gt8]

It very well could be valve train noise, if so give it a service with a good quality oil.

Injectors can make some noise, some more so than others. As for the 'up-to' 2500rpm, might be that you are a little paranoid and are hearing noises that might not actually be there.

[sonicii]

It's a bit strange that it only occurs when you start to accelerate, and not when idle. Makes me think 'exhaust manifold leak'.. That would also explain it only occuring when hot after everything expands. But the exhaust is on the opposite side of the heads to the intake...

[NISMO-61]

I doubt it might be the timing chain. without appropriate tools it's too hard to diagnose where the noise comes from, but i just did a quick check and, the noise wasnt there until the engine reached its normal temperature. then it started. the most possible location of the noise was the timing chain.

If so, what i do not understand is why it starts after warm-up and doesnt happen when the engine is cold?

Any idea>

[sonicii]

Oil is thicker when the engine is cold.. but I would expect the noise to be there all the time if it is a timing chain issue.

[Deep Dish V35]

a bit of backyard mechanics 101 here...

you can use a long screwdriver as a stethoscope.

press one end onto the part of the engine you want to listen to.

grip the handle with your thumb on the top of the handle.

press the tip of that thumb into your ear with a bit of pressure

the sounds travel up the screwdriver, thru the thumb and directly into the ear. if you can put the thumb tip onto bone it works better. you can listen in to various spots on the motor and almost pin point where its coming from

[Deep Dish V35]

^^ try it on injectors too if you can get to them

[NISMO-61]

Ok Let summarize the whole issue and put the pieces together;

the car makes that noise when the engine is warm, when its cold no noise at all.

when the car is in idle, no noise at all

if it's the timing chain, the sound should be there all the time, right?

If it is the injector, why would it do it when its only warm, but not do it when it's cold and why will itl make the noise after 1000Rpm and not after 2000-2500Rpm.

I'm just trying to put things together to understand the issue.

I will take it to Nissan hopefully this week and see what they come up with.

Please share any info & expertise you have as it would get back to you as appreciation.

regards

[Deep Dish V35]

id say its just one of those things that can only be determined with an audio clip

[PN-Mad]

change your oil (and oil filter) to a very good quality (grpV) 10-40w

do you know what oil is in it at the moment?

[NISMO-61]

Hi Guys,

Finally we figured out what the hack was wrong and it turned out to be the Variable valve Timing.....stuff. It seems like this is a common problem for this car as the mechanic didnt even think about it. He said he had three more V35 with the same issue.

When you remove the blue cap with the wires, there is no noise.

He said it costs $$$$$$ to get it fixed.

Other than higher fuel consumption, would that cause any harm to the engine if I unplug it and drive?

One more thing regarding the oil change, do you reckon it would make any difference. I'm thinking of getting Mobil 1 10-40W. how many liters do i need for this engine?

regards

[Deep Dish V35]

aparrently you can buy the servo's from dubai for $450 each. i cant get in contact with the guy who can get them tho

[PN-Mad]

question for oil - 5 litres- a full bottle. Go and buy oil filters for a 350z.

Regarding VVCT. No it will not harm your car. However, it will throw a CEL, it will lose a large noticeable amount of mid range, right where you drive the car daily ( there is no cam timing in the top end of the RPM map, it just helps with peak torque lower down- from my experience with VQ35s I really have NFI about VQ30DD maps).

Why don't you buy second hand from wreckers or Japan? Are you sure that it not working/broken? have you had error codes read?

[NISMO-61]

there was no error code at all. but when the mechanic removed the blue cap with wires there was no sound at all.

I already sent a message to one of the wreckers here in Melbourne. I know that they do have a few v35s. So we will see what they will say.

I was thinking of removing the cover of that variable valve timing unit which sits right beside the fan and the air filter unit in order to inspect the unit and see if there is any visible damage. however i'm a little bit reluctant as i dont know if I could do it or not. it seems like it has a few bolts holding it, but no idea what sort of gasket it has and whether it should be replaced or not.

Basically, i'm mechanically illiterate just trying to identify the exact problem so that i dont waste anymoney and get parts that i would not need.

I reckon I will take it to Nissan and get a comprehensive problem diagnosis and know exactly what the hell is wrong.

I appreciate your help and thanks hips.

[PN-Mad]

expect to be charged 150-250 bucks IF they will touch it.

I could tell you if you lived in Sydney for the beer economy.... but alas you dont.

I think the DD motors have electric servo assisted Cam angle variation. Rather than the hydralic unts in VQ35 motors. so not interchangeable. If it is actually working (varying cam angle), even if it clicks, leave it the fark alone.

The units are not silent, if your wondering...