1999 deville noise problem - Page 3

maeng9981 · #31 (**permalink**) 04-01-09, 01:05 PM

I found a few more things,
1. It is HARD to hear the noise when the car is backing up, but there IS the noise.
2. The noise is reduced when the coolant temp is low (below 100), the loudest noise when the engine is hot (near 210)

maeng9981 · #32 (**permalink**) 04-02-09, 12:30 AM

Here we go, this is the video I took yesterday.
http://www.youtube.com/watch?v=oNJ0FsDjGBc

You can hear the noise when the rpm is near 1400.
The camera loved to catch the "background" noise, so you may want to turn up the volume to hear the noise.

AMENCADDY · #33 (**permalink**) 04-02-09, 03:39 AM

I tried to listen but there was too much other noise for me to hear anything to revealing. i will think about it tho in case anything occurs to my brain.

DevilleRyDeR · #34 (**permalink**) 04-02-09, 07:01 PM

Yea I didnt hear anything. Does it happen when your sitting still and revving up the engine? or only when you are moving?

maeng9981 · #35 (**permalink**) 04-02-09, 09:45 PM

OK I'm finding an audio recorder which is way better than the camera's built-in microphone. I'll re-record the noise as soon as I find the recorder.

It happens when the engine runs at near 1400rpm under any circumstances.

maeng9981 · #36 (**permalink**) 04-09-09, 12:39 AM

Sorry about the old video. Here are new videos! (I couldn't find the recorder though.)
You can definitely hear the noise in the videos and I put some sticky notes when the noise happens.

YouTube - Noise

YouTube - Noise

These 2 videos are almost the same.

Here's some more information, the privious owner had had a broken serpentine belt while driving. I guess it could cause some problems like this..

aac123 · #37 (**permalink**) 04-09-09, 02:18 AM

hey man good post with the video and all I had the exact same noise when driving from start till about 25-30 mph. Well u know how cadillacs are low to the ground and all had a pea size dent on catilyc converter, put new OEM in and whoila no more noise hope that helps

layta

mgb4tim · #38 (**permalink**) 04-09-09, 02:53 PM

see if your exhaust is sagging and hitting any of the small cross members bolted up under the car.

AMENCADDY · #39 (**permalink**) 04-09-09, 06:18 PM

Doesn't sound like muffler hole noise but something is obviously loose enough to resonate and make that noise when your drive train is reading the afore mentioned rpm. I bet you could find it pretty easy if you climb under there (when the car is cooled down of course) and start a hands on exploration, until you find what it is. Could very well be something in the muffler system that is loose . I doubt that the noise will go away on its own tho' and might even get worse if not corrected (duh! that thought occured to me after I had my morning coffee! LOL!) Also, how loud is the noise? I mean do people turn their head and give you dirty looks when you are next to them and the noise is happening or is it only loud enough for your ears?

maeng9981 · #40 (**permalink**) 04-09-09, 07:52 PM

Thank you for your replies.

I let the shop to replace catalytic converter, as well as HG, a year ago.

Only people IN the car can hear the noise, but there is no noise outside of the car. One day I let someone drive the car and tried to listen to the noise on the outside, but I couldn't hear anything.

I will check for loose things under the car this weekend. Thanks!

hystat · #41 (**permalink**) 04-18-09, 12:45 AM

yeah, that's the exhaust pipe rubbing on the cross brace. In reverse the engine torque pulls the pipe up and off he brace.
In forward, the torque pushes the pipe down.

I went through this recently. Drove me nuts. Hearing yours makes me feel uneasy. I so hated that noise!!!

I finally blocked the car up safely, used a large wood block and the power seat to lock brakes on, then tied a wire to the throttle and did a torque stall while laying under the car.

Sure enough, the pipe was touching the brace. Funny thing though, even laying under the car with my ear right next to the pipe, there was NO sound.

Inside the car, the sound was very loud.

I bent the hanger brackets to lift the pipe. Silence!

00teq · #42 (**permalink**) 10-25-09, 07:07 PM

how can i correct that problem i have the same issue with my 99 deville
...i notice that exhaust pipe is hitting the c/mem. but there badly bent ..
it will on make the noise while in drive mode ,at first i was think that harmonic
balancer was action up because it would only do it while taking off

!!please help
and thanks for your advise!!!

maeng9981 · #43 (**permalink**) 10-26-09, 06:44 PM

I haven't figure this problem out since I traveled abroad in this summer and my aunt has been driving the car since I left. She went to a shop, and the shop removed something look like cross brace. But the noise is still there. I will soon take a day to figure out where the "removed" part originally belonged to, and to find if there is a loose point.

00teq · #44 (**permalink**) 10-27-09, 12:48 AM

well I'm sorry to hear that you haven't fight that problem,gonna get under the car this weekend and figure it out!!!!!!the sound gets under my skin,and to think that it started two weeks ago.my wife recalls going over a speed and the car bottom out and hit the bump and thats when the noise started.
while driving upon take off the noise is heard by the hump right in that area

i'll keep you posted!!!!!