bluenoise

Since this comes up quite a bit, I thought I'd share the solution that worked for me. I've shared this with a few here via PM, but here's the details on how to make your trip to the dealer a single-trip repair.

The basis for this is that virtually all rattles have a resonant frequency. Once you find it, you can easily reproduce it for the tech without driving all over town trying to get it to buzz again for the tech. Each rattle will have its own frequency, so with some patience, you should be able to isolate all or most of them.

Hardware needed:

- A computer with an audio output. I have an Apple Powerbook, but any laptop with an audio port will work. If you don't have a laptop, you could use a desktop machine setup in your garage for this project, but it's certainly not convenient.

- A cassette adapter. These are generally used to feed an MP3 player into a car's cassette deck. They sell them at Radio Shack, Best Buy, etc. It looks like a cassette, but it has an 1/8" miniplug on a cord hanging out of it. This will allow you to get the sound from your computer into the car's stereo system.

- Blue painters' masking tape. You'll use this to note the locations of the rattles. I doesn't leave residue.

- A Sharpie marker for marking the tape.

Software needed:

- Sine wave generator. I use a soft-synth from Native Instruments, but there are a large number of shareware and freeware programs available for this. This Google search (http://www.google.com/search?hl=en&...tor%22+freeware) turns up lots of hits for this.

Procedure:

1. Load up the software and learn how to generate sine tones at low frequencies, such as 50 Hz.

2. Connect the computer to the car's cassette deck using the cassette adapter. Plug the adapter into the computer's audio output and plop the cassette into the car's head unit.

3. You should be able to hear the sine tones out of the car's speakers. Mind your car's battery, though, to make sure you don't kill it during this process.

4. Starting with the tone at a low frequency, such as 10 Hz, turn up the stereo loud enough to hear the speakers trying to shake things. Be careful not to go too loud as you don't want to damage your stereo or speakers.

5. Slowly increase the sine's frequency 1 Hz at a time until you hear something start to buzz. Track down what's buzzing and see if you can isolate it. Once you find it, mark it with a piece of blue painters' tape with the frequency written on it. If you find a buzz at 23 Hz, for example, write "23 Hz" on the tape and stick it to the spot that's rattling.

6. Continue increasing the frequency and noting the buzzes until you can't find any more, or can't take the noise. Once you're up to about 300-400 Hz, you're probably going to really hate the sound and there likely aren't any rattles in that range anyway.

7. Once you've found all the rattles, use the software to generate audio files of the specific sine tones. For example, if you found rattles at 23 Hz, 48 Hz, and 57 Hz, generate those three audio files. Make them each at least a minute long.

8. Burn these audio files to an audio CD and note the tracks. For example, "Track 1 - 23 Hz," "Track 2 - 48 Hz," etc.

9. Replace the pieces of blue tape with new ones labeled according to the track numbers. So replace the tape that said, "23 Hz" with one that says, "Track 1."

10. Document the nature of each buzz and the necessary volume setting to excite each buzz so you can give the printout to the service tech along with the CD. Explain to them that they need to play each track to excite the marked locations of each rattle. In theory, once the rattle at each piece of tape has been eliminated, there should be no more rattles.

I had several rattles and they fixed them all using this method. I hope it works for you.

TLTrance

Totally random hijack, but where are you located in the Bay Area, bluenoise?

bluenoise

East Bay, near Walnut Creek

TLTrance

San Jose here... The only vibration that bothers me are:

1. Driver side window/door frame... Its not necessarily frequency specific.. I know its basically plastic on frame, because it can't be the window if its flush against the area/side where the window meets up the felt trim.

2. Driver side seat belt tensioner. It sounds like a spring that's vibrating against the plastic.

bluenoise

I had quite few ranging from passenger door map pocket to the ceiling near the moon roof. One particularly annoying one was in the vicinity of the left tweeter on the dash. The road near my house is rough and it revealed every rattle imaginable. However, the roads near the dealership are all quite smooth, so I knew I'd have trouble getting the tech to reproduce them.

After all was said and done, here's what it took to fix the rattles:

- New ceiling installed with the better clip system
- New subwoofer
- New map light console
- New glove box
- Fixed some clips in the passenger door
- Lubed door seals
- New vent assembly left of the gauge cluster
- Added foam to storage trays under radio and near cup holders
- Added slippery tape under some trim pieces

All under warranty and all in three days while I drove a loaner.

One of the rattles that keeps coming back is the passenger seat belt. After I've had a passenger, the belt doesn't retract such that the clip is in a good position and it rattles against the B-pillar. Now, it's just habit to fix it each time someone gets out.

Tom Champagne

I just got my 04TL fixed due to some rattles. I got a new glovebox and new storage compartments. So far so good...the service tech told me that the storage compartments is an ongoing issue and that they've been "redesigned",but the glovebox was a new one(problem area) for them.

Adobeman

Very cool. I have done this for my home theater to find rattling windows, picture frames, etc. but never thought of it for the car.

I would just re-emphasize your word of caution about watching the volume. In your step 4 you say 10Hz. I'd be EXTREMELY careful with continuous tones below 30 or 40Hz. It's not all that hard to destroy drivers below that. Especially the stock ones.

bluenoise

Good point. I was careful not to exceed a setting of 10 on my volume control during most of these tests, especially since the output from the computer was full-volume line level.

If you hear any sound coming out of the speakers while doing this test at a frequency setting below about 25-30 Hz, it's probably the sound of the amplifier and/or speakers distorting, so turn it down or off immediately. It doesn't take much volume to do the tests or damage your system.

bluenoise

I should add that it's a good idea to note the volume setting when making the labels. Not every rattle happens at the same volume, so it's best to find the quietest volume that still excites the rattle. There's no reason to make the volume harsh for the tech or your system.

6spMike

Awesome, Bluenoise!!
Thanks!!

Drew408

I have the same problem in my 2006 TL, I brought it to the Los Gatos Acura and they said they couldn't do anything about it.