need help with locating a noise..! - Land Rovers Only

DiscoDoggII · 08-12-2008, 07:02 PM

Hey guys...I am completely out of ideas and was hoping someone could point me in the right direction. My disco is making a loud whistling sound and i cannot locate what it is coming from. Normally the sound doesn't start on start up, but as soon as you give it the gas and let off the gas, you hear a high pitched whistling noise. As long as I hit the gas the sound isn't there, but it comes right back as soon as you let off...!! I was told i should clean the Idle Air control valve, so i did that..!! And that didnt help...!! So instead of dropping a load of cash on something i was unsure of, i bought another IAC valve on ebay that was used...!! I just replaced the part this afternoon, but again it makes the noise..!!

So either its not the problem, or i got ripped off...but im not judging..!! My question is....has anyone else had this noise? what are some other possibilities...?? or do i just need to bite the bullet and give up my amateur mechanic work and take it to someone who knows what they are doing???
please anyone with ideas will be greatly appreciated..!

thanks

Rover Kid · 08-12-2008, 07:47 PM

It sounds like your idler pulley. I had the same problem and a quick replacement did the trick. Take a flashlight with the engine running and look at the independent pulleys and see if it may be wobbling or not. If that's the problem you should see it moving (wobbling), then I'd replace both at the same time. Good luck in fixing the problem.

Alak · 08-12-2008, 09:53 PM

A pulley noise would be constant and would change in pitch with engine speed. If theres no noise under accelleration, then you have a vaccuum leak because vacuum pressure is less when the throttle is open.

I usually use an areosol can flamable substance like brake cleaner (some are non-flamable) and spray it a little at a time around the engine. When it stumbles, or reacts, you have found your source of leak. Your looking to spray around vaccuum lines or other possible areas.

tempestv8 · 08-14-2008, 07:04 AM

If your gas cap is faulty, you will get a low pitch whine too, as the fuel system is pressurised.

DiscoDoggII · 08-14-2008, 05:02 PM

Thanks guys.... i will check out a few of these suggestions....and let you know which one is the winner.....thanks again...!!

DiscoDoggII · 08-15-2008, 11:50 AM

Hey Alak, when you use the spray to find the vaccuum leak, can this be any FLAMMABLE spray?? like WD40 or type of substance like that.... just wanted to double check on the flammable too..!! i took a look at my pulleys all around the serpentine belt...but all seemed fine....none had a wobble effect to them...!! also, the noise seems to be further to the back on the motor...which had me thinking it was the IAC valve in the first place, its just such a loud high pitched noise that its kinda hard to figure out exactly where it is coming from...! So im going to try your idea before i start replacing pulleys.

DiscoDoggII · 08-18-2008, 06:47 PM

okay, so i tried the aerosol spray around the vacuum lines and had no reaction or stumble with the motor. I also checked the pulleys to see if there was any wobble, but there doesn't appear to be any wobbling going on with any of them. From what i can tell, the sound is definitely simultaneous with the sucking of air...which makes me believe it is definitely a vacuum problem. Someone also suggested a possible intake valve problem....but they don't own any rovers....so could this be a common problem? any other diagnostic checks for vacuum leaks before i take it to a garage?

Pinarello · 08-18-2008, 08:33 PM

I am absolutely on board with the vacuum leak diagnosis...if i were to take a look, I would start with all 90deg bends in tubing AND the flexible parts of the air-intake hose. I have had ones on my Land Cruisers crack AFTER the MAF and just suck air. Look on the bottom, nearest the engine heat. Likely too it is exacerbated when the engine is warm and the rubber/plastic parts get pliable and will separate more easily in the heat. I also subscribe to the flammable aerosol trick, but stick to the light and flammable...a-la starter fluid/ether and brake cleaner. if your leak is on the bottom of a hose, the aerosol may not be getting ingested into the intake. Keep after it dude...
Todd

DiscoDoggII · 10-02-2008, 06:21 PM

I may finally have a resolution to the mystery noise..! After taking my truck to several mechanics who all said I definitely have a vacuum leak somewhere, but just scratched their heads as to where the leak actually was coming from....one finally to out his stethoscope to pin point the leak. He told me he believes the vacuum leak is coming from the upper intake plenum gasket. Told me he could probably get the job done for about $200 plus parts..!

But before I actually drop any more cash into the problem, I just wanted see what you all thought about his diagnosis..??? Has anyone had this issue before??? And what degree of difficulty is a fix of this nature (should i get my hands dirty or leave it to a pro)??

DiscoDoggII · 10-02-2008, 06:28 PM

Oh yeah....also forgot to give you all a bit of information...!! I took my truck off road just after this diagnosis..!! As soon as I took my truck through a few creeks and had some steam rise into the engine from hitting the water.....the noise disappeared..!!
Strange I know..!!! But after a day of drying out, the noise came back..!!

I'm guessing that the steam caused the gasket to swell and seal the leak..!! as soon as it dried back out...the noise came back..! Could this confirm the plenum gasket theory?

08-12-2008, 07:02 PM	#1 (permalink)
DiscoDoggII Member Join Date: Jan 2007 Location: Southwest, VA Posts: 22 Gallery: 0	need help with locating a noise..! Hey guys...I am completely out of ideas and was hoping someone could point me in the right direction. My disco is making a loud whistling sound and i cannot locate what it is coming from. Normally the sound doesn't start on start up, but as soon as you give it the gas and let off the gas, you hear a high pitched whistling noise. As long as I hit the gas the sound isn't there, but it comes right back as soon as you let off...!! I was told i should clean the Idle Air control valve, so i did that..!! And that didnt help...!! So instead of dropping a load of cash on something i was unsure of, i bought another IAC valve on ebay that was used...!! I just replaced the part this afternoon, but again it makes the noise..!! So either its not the problem, or i got ripped off...but im not judging..!! My question is....has anyone else had this noise? what are some other possibilities...?? or do i just need to bite the bullet and give up my amateur mechanic work and take it to someone who knows what they are doing??? please anyone with ideas will be greatly appreciated..! thanks

08-12-2008, 09:53 PM	#3 (permalink)
Alak 2002 Discovery II SE Join Date: Sep 2007 Location: Alberta, Canada Posts: 356 Gallery: 0	A pulley noise would be constant and would change in pitch with engine speed. If theres no noise under accelleration, then you have a vaccuum leak because vacuum pressure is less when the throttle is open. I usually use an areosol can flamable substance like brake cleaner (some are non-flamable) and spray it a little at a time around the engine. When it stumbles, or reacts, you have found your source of leak. Your looking to spray around vaccuum lines or other possible areas. __________________ 2002 Discovery Series II SE. 2" OME Heavy Duty. 265/65R18 BF Goodrich All-Terrain T/A's. I told my wife if the Land Rover goes, so do I. That shut her up.

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08-12-2008, 07:47 PM	#2 (permalink)
Rover Kid Member Join Date: Oct 2007 Posts: 18 Gallery: 0	It sounds like your idler pulley. I had the same problem and a quick replacement did the trick. Take a flashlight with the engine running and look at the independent pulleys and see if it may be wobbling or not. If that's the problem you should see it moving (wobbling), then I'd replace both at the same time. Good luck in fixing the problem.

08-14-2008, 07:04 AM	#4 (permalink)
tempestv8 Member Join Date: Jul 2007 Location: Melbourne, Australia Posts: 51 Gallery: 0	If your gas cap is faulty, you will get a low pitch whine too, as the fuel system is pressurised.

08-14-2008, 05:02 PM	#5 (permalink)
DiscoDoggII Member Join Date: Jan 2007 Location: Southwest, VA Posts: 22 Gallery: 0	Thanks guys.... i will check out a few of these suggestions....and let you know which one is the winner.....thanks again...!!

08-15-2008, 11:50 AM	#6 (permalink)
DiscoDoggII Member Join Date: Jan 2007 Location: Southwest, VA Posts: 22 Gallery: 0	Hey Alak, when you use the spray to find the vaccuum leak, can this be any FLAMMABLE spray?? like WD40 or type of substance like that.... just wanted to double check on the flammable too..!! i took a look at my pulleys all around the serpentine belt...but all seemed fine....none had a wobble effect to them...!! also, the noise seems to be further to the back on the motor...which had me thinking it was the IAC valve in the first place, its just such a loud high pitched noise that its kinda hard to figure out exactly where it is coming from...! So im going to try your idea before i start replacing pulleys.

08-18-2008, 06:47 PM	#7 (permalink)
DiscoDoggII Member Join Date: Jan 2007 Location: Southwest, VA Posts: 22 Gallery: 0	okay, so i tried the aerosol spray around the vacuum lines and had no reaction or stumble with the motor. I also checked the pulleys to see if there was any wobble, but there doesn't appear to be any wobbling going on with any of them. From what i can tell, the sound is definitely simultaneous with the sucking of air...which makes me believe it is definitely a vacuum problem. Someone also suggested a possible intake valve problem....but they don't own any rovers....so could this be a common problem? any other diagnostic checks for vacuum leaks before i take it to a garage?

08-18-2008, 08:33 PM	#8 (permalink)
Pinarello Senior Member Join Date: Aug 2008 Location: Crystal City, Va. Posts: 145 Gallery: 0	I am absolutely on board with the vacuum leak diagnosis...if i were to take a look, I would start with all 90deg bends in tubing AND the flexible parts of the air-intake hose. I have had ones on my Land Cruisers crack AFTER the MAF and just suck air. Look on the bottom, nearest the engine heat. Likely too it is exacerbated when the engine is warm and the rubber/plastic parts get pliable and will separate more easily in the heat. I also subscribe to the flammable aerosol trick, but stick to the light and flammable...a-la starter fluid/ether and brake cleaner. if your leak is on the bottom of a hose, the aerosol may not be getting ingested into the intake. Keep after it dude... Todd

10-02-2008, 06:21 PM	#9 (permalink)
DiscoDoggII Member Join Date: Jan 2007 Location: Southwest, VA Posts: 22 Gallery: 0	I may finally have a resolution to the mystery noise..! After taking my truck to several mechanics who all said I definitely have a vacuum leak somewhere, but just scratched their heads as to where the leak actually was coming from....one finally to out his stethoscope to pin point the leak. He told me he believes the vacuum leak is coming from the upper intake plenum gasket. Told me he could probably get the job done for about $200 plus parts..! But before I actually drop any more cash into the problem, I just wanted see what you all thought about his diagnosis..??? Has anyone had this issue before??? And what degree of difficulty is a fix of this nature (should i get my hands dirty or leave it to a pro)??

10-02-2008, 06:28 PM	#10 (permalink)
DiscoDoggII Member Join Date: Jan 2007 Location: Southwest, VA Posts: 22 Gallery: 0	Oh yeah....also forgot to give you all a bit of information...!! I took my truck off road just after this diagnosis..!! As soon as I took my truck through a few creeks and had some steam rise into the engine from hitting the water.....the noise disappeared..!! Strange I know..!!! But after a day of drying out, the noise came back..!! I'm guessing that the steam caused the gasket to swell and seal the leak..!! as soon as it dried back out...the noise came back..! Could this confirm the plenum gasket theory?

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