dab996

http://youtu.be/575JKEOZBNc.

Hi, I have read through the forum to see if anyone else has the same or similar problem but as yet I am at a loss and so is my local OPC. Above is the address for the video of the chirping noise and apologies for the erratic videoing. This chirping noise has been going on for months as it was initially suggested by my OPC that it sounded like a pulley on the water pump. Today it went in to the OPC for what was supposed to be a water pump replacement but alas they confirmed this wasn't the problem and they were at a loss to diagnose what other than it was coming from the left bank side of the engine. They ruled out IMS, AOS and Serpentine and suggested that until they got inside the engine and even then no guarantees, would they no what the problem is but so far its a head scratcher.

I should note that the noise stops on long runs when the engine is really up to temp and there are no diagnostic issues, it doesn't use much oil and touch wood, runs sweetly.

Any help suggestions would be greatly appreciated.

Thanks,
D

porsches996

AOS..!!!!!!!!

dab996

AOS ruled out

Mark I

Suggest the usual test. Remove the belt & run for short time; if noise is gone, rotate turning components by hand for excess play, resistance, etc. GL with fix.

dab996

Done all the belts, AOS and IMS tests and the OPC has ruled these out. New suggestions have been a loose spark plug or exhaust gaskets so will take back to garage to check.

kpl

does the noise vary with engine RPM, or only occur at idle? Sounds silmilar to when the idler pulley on mine started to go. It eventually turned into a aweful grinding noise that sounded like my motor was self destructing. I'd take it somewhere else to get another opinion (and don't tell them what's been looked at already) before tearing into the motor.

function12

Does it go away when the clutch is depressed?
Sure sounded louder on the drivers side by the exhuast manifold. Lose plug.

Macster

Assuming the OPC's correct in eliminating the source of the noise is belt or accessory drive related, then my money is on an exhaust leak. A not too close second is a loose spark plug. In the case of a plug the noise I believe would be present all the time, while an exhaust leak can go away if the hole closes as the exhaust system heats up and the hole (probably a crack) closes.

A suggestion: You really should arrange to get the car in the air safely and arrange to get under the car with a stethescope (or with a mechanic who has one) and give a listen to narrow down the source of the noise.


Now not only do you use your ears, you use your nose to detect any smell of a leaking exhaust. It may have a bit different odor than the exhaust from the exhaust outlets, depending upon where the leak is and how severe it is.

You can see if you can spot the leak by using a feather.

Buy a feather duster and use a feather to run it along side but avoid touching the feather to the hot exhaust and see if you can spot the feather react (flutter?) when it passes through/by the exhaust leak.

If you touch the feather against the hot exhaust just toss it and grab another.

(As an aside: to find leaks in high pressure/high temperature (hundreds of PSI and hundreds of degrees above boiling) steam piping such as are found in ship propulsion systems instead of a feather a wooden broom stick is used. When the broom stick is passed through the leak the steam cuts through the stick like a band saw blade.)

But before you do the feather test you need to get the car in the air and pinpoint as close as possible to where the noise is coming from. You might get lucky and find the source without having to use a feather.

Sincerely,

Macster.

Pac996

For a new one I thought maybe a motor mount till I listened to the video. Since the noise increases "when the vlave covers are viewed" it made me think uh oh miners trapped in thee trying to pick axe their way out. But trying to think easy fix it could still be the motor mount <crossed fingers>. Just because the video shows the valve area doesn't mean it isn't reflecting off of parts in there or noe being transmitted through metal paths.

My seat of the pants estimate of rpm and valve activation tells me its 700rpm/30=23.3 intake or exhaust manipulations per second. Not like that matters to a gummed up or collapsing lifter.

Since it sounds like a chirp there is exhaust bracket loose hint hint, internal exhaust loose instead or rattling its rubbing its dry metal chirping, and plain old proof the end of the world really is coming this winter

I'd go simple with the engine cold checking header bolts and exhaust for tightness by first trying to move then trying a slight tightening of each and every bolt you can get to. Even the hangers.

Good luck with it not being internal.

Black_on_black

The frequency of chirp suggests accessory belt, idlers or bearings in generator, pump, A/C or servo. How did they rule those things out?

IanDenker

Was this ever sussed out? I have a similar albeit less prominent noise from the same spot. It goes away after warm up etc. I just had the aos replaced less than 1000 miles ago.

5CHN3LL

Ian, have you tried running it briefly with the belt off? If no belt = no squeak, it's an accessory or idler pulley.

bal

Possibly the coolest thing I've read all week...

IanDenker

No, I haven't tried that. There seem to be mixed reviews on running the engine without the belt on. I am thinking of doing the plugs, maybe racking it and use a stethoscope to pinpoint the sound. What are your thoughts on running it without the belt on??

BTW- thanks for the response!

Soaringman

Run with belt off for a very short time, because of coarse you'll have to water pump etc.,,