np20412

John, you were right. It's NOT the gas cap. I replaced the gas cap today and the hissing is still there just as much as before. Any ideas where to start looking next? How can I check to see if the charcoal canister and its components are working properly? This hiss is very annoying!

neurocity

iTrader: (17)

Wow, Im surprised its a deeper problem.

TheMole

iTrader: (13)

You said that it does not make the sound when you rev it during standstill and only makes the sound while the car is in motion so you might be able to rule engine related stuff out. Would a blown rear shock make this kind of sound? Might be suspension related or something like wheel bearing.

np20412

lol its definitely NOT a wheel bearing, I just had essentially all of them replaced because they were bad. I know what a busted bearing sounds like, and its not like this. this is really like a sound of air or something rushing through somewhere as I drive. When I accelerate, the pitch of the noise increases, as and as I decelerate it decreases. Bad wheel bearings give a rotational sound, this is constant. Did a corner bounce test, all shocks are fine and the car isn't bottoming out anywhere.

TheMole

iTrader: (13)

How about exhaust leak? Weather stripping or window molding? I'm just throwing stuff out there haha.

np20412

haha thanks for the ideas, I have an aftermarket exhaust setup, and I don't think its leaking because I don't an exhaust leak would make this type of sound...might be a weatherstripping thing as it sounds air rushing, i'll have to check everything again but again i doubt thats what it is

I am going to find a hill, turn the car off and put it in N and let it coast down the hill. I want to see if the same noise appears. If it does, then it means the noise is definitely coming from an air leak or from the suspension. I just dont think anything in the suspension can make this kind of a noise though.

neurocity

iTrader: (17)

Ok...not the gas cap (which sucks)

If the fuel pump was sucking in air or somehow creating suction, the car wouldn't run right.

If one of the covers was loose and air was getting sucked in that way, you'd smell gas, and the car wouldn't run right.

You got rear ended while you were at a stop, maybe the force of impact while your brakes were applied screwed something up there...but then you'd have a noticeable brake problem.

Your wheel wells are ok right? No cracks in there? cause that might be muffled (with rear seat) road/tire noise.

Its not the static whine you hear in speakers, when there is a bad ground..That will usually increase decrease with RPMs

all your windows are cool? like you the rear seals are ok, the same (Matching) protrusions of weather stripping and glass.

The new bumper and deck-lid lines are even and "fitted" looking? nothings sticking out?

I know....Its because you removed the wing and changed the airflow over the car!!!

np20412

LOL! I wish that was the reason, but this is really weird. It seems all the body panels are lined up properly as they should be. The wheel wells are clear from all obstructions and are fully in tact. Weatherstripping is uniform and exists all around the outside of the windows and inside the doors. I am going to have to tear apart the trunk and look, I am getting a WATER LEAK somewhere inside my trunk around that area because last time it rained, my amplifier got soaked and stopped working for a little while until it dried up. I checked all the drain tubes from the gas lid area and from the sunroof, those were all connected properly and clear of obstruction. I did a water test and it all drained properly. I poured water around that entire area and I did not notice any water inside the trunk anywhere. Since then it hasn't rained again so I haven't been able to get a real test again. BUT if there is a water leak from one of the body panels after the new parts were installed, that would explain the sound of air rushing and the sound getting more and more prominent as speed increases, and nonexistent at low speeds or at a stop. ALSO when I roll down the windows, I can't hear it anymore because of the ambient noise. I feel as though if it were something in the suspension, I would still be able to hear it at low speeds as the sounds would echo to outside of the car. The more I think about it, the more it seems like air is not flowing fully over the outside of the car and is instead being sucked in somewhere as it passes over the outside of the vehicle...

JohnEd

iTrader: (1)

NY,

Walk with me here a ways. You are not really sure where, exactly, the noise is coming from....correct? That would be good info to collect. Problem is the accoustics in the back seat of a Lex can be deceiving, as is true in any car. You need some sort of "directional" mike. I think you can make this device by modifying a stethascope and then using it to more closely determin the source of the noise. Try getting ahold of one of those cheapy auto stethascopes and modify it accordingly: Replace the rod used to pick up the engine noise with a "plastic" funnel with a 3 inch mouth(or bigger). Use the funnel as a parabolic reflector hooked up to the tube(s) of the steth. With someone else driving you can point the funnel/pick-up at the various locations and determin the source. Try pointing the funnel at the rear window from about a foot away and see what you hear at 60mph.

Really want to know how this works out...OK?

Good hunting,

John

np20412

John,

I can definitely tell you that the noise is coming out the passenger side rear, where the fuel door and right rear speaker area is. I know this for a fact, as I have sat in the backseat with someone else driving and monitered from the right side to the left side. It sounds as though its coming from directly behind the rear inside panel opposite where the fuel door is. I am going to take out the rear seat completely right now and tomorrow I will drive without it installed, to see if the sound becomes anymore audible and perhaps easier to pinpoint. I will update tomorrow along with shooting a new video of the noise hopefully so that it will be more audible to everyone!

JohnEd

iTrader: (1)

When I took out my rear seat I found a solid wall of sheet metal. There were two channels/cavities that went into the trunk along the underside of the top of the fenders. I put an extension hose on a can of triple expanding foam and emptied the can in there. Trust me, it no longer connects to the trunk and my noise went down somewhat. The fenedr is sure "dead" now.

Let us know what you find.

John

np20412

ARGH. I took the rear seat out and the hiss was noticeable louder from the right rear area. I can't figure this crap out for the life of me. I am more and more beginning to think its something in the wheel/suspension/brake setup. Would a dragging brake pad make a hiss even if it was dragging just a very little bit? I don't think its dragging because performance seems normal and coasting results in a decrease of speed at a normal rate (with a dragging pad, decrease in speed would be faster and idle speed slower). It's DEFINITELY NOT in the fuel system, as I cutoff the engine and rolled the car down a hill in N and still heard the noise.

nextlevelcoupe

iTrader: (1)

rear water leak fix:

https://www.clublexus.com/forums/sho...ght=water+leak

nextlevelcoupe

iTrader: (1)

not sure what your hearing but it could be your differential. when it begins to wear, it gives of a hissing then "whooping" noise... especially since you hear this noise while the car is in motion..

np20412

UGH, I HOPE THATS NOT IT

I can't afford to replace the differential, I would have to sell the car.