TravisCadello

01 SE 5speed, Not sure if this is normal or not but what i thought was a whistling sound of my new intake is NOT, I hear a Vaccum leak,Sounds Large cause at idle its louder then my air filter when i put my ear right next to it.


I hit the gas in N and the whistle i been hearing when shifting gears and hiting gas again was comming from under the Throttle Body Very hard to pin point but dont know if this is normal or not, i hear it with my ear by throttle body but sounds like under the IM. What Commonly goes out on these vq30s? could it be IM gasket or throttle body gasket?


What gets me is that it Runs Great and smooth,but doesn't start up like it should and doesn't have the low end power like it should.

it has 204k miles and notthing looks messed with.

noahrexion

Please elaborate on what "my new intake" means.

What did you go messing with? What was installed/what work did you do...etc
Do you still have the stock setup? Do you have any CEL? Do you have any brake cleaner?

TravisCadello

I put a MAF adapater and a high flow air filter thats it...and ill get brake cleaner today n see if its leaking or not.

TravisCadello

Well sprayed all around & notthin! i know forsure i hear a vaccum and plus my intake is way too quiet compared to my 4th gen.

5th gen dd

I have a similar problem on my '01 GLE with 86k miles. There is a whistling sound at medium to heavy throttle coming from under/inside the IM that can be heard both inside and outside of the car. I've also attempted to locate a leak using aerosol spray. After no luck I went ahead and removed and cleaned the upper IM.

When I took the manifold apart to clean it I noticed a few of the o-rings on the power valve were cracked, creating a gap where the o-rings seal the valve between the runners on the intake. The UIM went back on with new gaskets and the noise still persisted. Unfortunately, I was not able to locate any o-rings in time before putting the manifold back on and new upper intake manifold and throttle body gaskets definitely did not improve the noise for me.

I'm thinking the whistling sound may be coming from the air rushing through the gaps I saw. Other than a drop in K&N filter my intake assembly is stock. No EGR either. The car runs and idles fine and gets average mpg so it just seems to be an annoying noise in my case. My GF's brother just bought a 00' GXE 5spd and I had to drive it home for him because he couldn't drive stick yet. I noticed right away the difference with no whistling. I also noticed right away after driving his car once for 20 minutes that I was ready to rip the automatic out of mine and drop a 5 spd in. But that's for another thread...

I would think if this issue was bad enough it would affect low end driveability if the valve is not functioning properly due to bad seals. Either that or possibly something I overlooked with the lower IM. I even changed all the surrounding items like the PCV assembly (grommet, valve, hose) and the vent hose running between the valve covers on the front of the engine.

TravisCadello

Hmmm....Thats weird and yeah i thought for little bit that maybe the updated IM just naturally makes that sounds but haven't heard any other 5th gens n person to compare.


theirs diffidently a leak somewhere but guess ill wait for it to become a problem so i can find it.

Aviation005

I used to have the same vacuum leak sound in my intake (2002 3.5)
It was a PCV valve that had no gasket on it! It created a vacuum leak
-There was a time when nissan stopped selling the gasket with the PCV valve, this caused huge oil burning issues, my 3.5 was burning a QT ever 700, after getting a new PCV and fixing the valve cover, im not losing any oil

my car also lacked low end power, please check your pcv valve, make sure the gasket is in top shape and the piece inside moves freely when you shake it