Let's play "Name That Sound!"

[Smalls]

Greetings All,

I'm having a bit of a problem troubleshooting a sound that emanates from the engine bay. The sound closely resembles a very weak horn. It's a low tone. It's happens from 1st through 3rd gear. The noise starts at approx 1800 rpm and continues through the rpm range while under any amount of throttle, weather it would be light, moderate or heavy. It does NOT make the sound in 4th or 5th.

It doesn't sound high pitched enough to be a boost leak. Second, it would do it in all gears, not just the first three. I can't duplicate it in neutral while revving the engine. I thought about the turbo making it's way out, but wouldn't that be more prevalent under heavy loads at full boost? (IE 4th or 5th gear pull)

I did have an issue a few weeks ago with a slipping clutch in 3rd or 4th, while under heavy go-pedal. During this time was a notchy 3rd or 4th gear selection. This only acted up after sitting in traffic or a solid romp session. A few weeks later, I no longer have a shifting issue or a slipping issue under the same conditions. The car "fixed" itself. Could the noise I'm hearing be clutch related?

The car:

2001 Jetta with 265k
EGR Delete
PD150 intake with race pipe.
Newer cam, head and timing belt (sub 10k miles ago)
All fluids changed. Liqui-Moly 75-90 gl5 (bad idea?) in trans.

I don't notice any negative performance while the noise is being made. I'm getting ready to flash a Malone Stage 1 and wish to fix any problems I may have.

 

[oilhammer]

Is it possibly coming from the transmission? Do you have a [safe] way to lift the front of the car and run the wheels up and listen from underneath?

 

[Smalls]

I do have access to a post lift.

I didn't even think about it being internal to the trans. I'll have to check it this weekend.

 

[HogWrangler]

If you can, after you get the car running put it in neutral and cut off the engine. It will be a whole lot easier looking for a noise. Unless the engine has to be running to hear the noise

 

[Smalls]

If you can, after you get the car running put it in neutral and cut off the engine. It will be a whole lot easier looking for a noise. Unless the engine has to be running to hear the noise

It doesn't exist at idle. It also doesn't exist with a blip of the throttle. Only under accel. I need to put it on the lift and maybe grab a video.

 

[JDSwan87]

Greetings All,
I'm having a bit of a problem troubleshooting a sound that emanates from the engine bay. The sound closely resembles a very weak horn. It's a low tone. It's happens from 1st through 3rd gear. The noise starts at approx 1800 rpm and continues through the rpm range while under any amount of throttle, weather it would be light, moderate or heavy. It does NOT make the sound in 4th or 5th.
It doesn't sound high pitched enough to be a boost leak. Second, it would do it in all gears, not just the first three. I can't duplicate it in neutral while revving the engine. I thought about the turbo making it's way out, but wouldn't that be more prevalent under heavy loads at full boost? (IE 4th or 5th gear pull)
I did have an issue a few weeks ago with a slipping clutch in 3rd or 4th, while under heavy go-pedal. During this time was a notchy 3rd or 4th gear selection. This only acted up after sitting in traffic or a solid romp session. A few weeks later, I no longer have a shifting issue or a slipping issue under the same conditions. The car "fixed" itself. Could the noise I'm hearing be clutch related?
The car:
2001 Jetta with 265k
EGR Delete
PD150 intake with race pipe.
Newer cam, head and timing belt (sub 10k miles ago)
All fluids changed. Liqui-Moly 75-90 gl5 (bad idea?) in trans.
I don't notice any negative performance while the noise is being made. I'm getting ready to flash a Malone Stage 1 and wish to fix any problems I may have.

I seem to remember reading somewhere that GL4 is what's needed in the 02J and the GL5 is actually BAD for them...

EDIT: After a little digging, I can't seem to back up my memory...

 

[Smalls]

I seem to remember reading somewhere that GL4 is what's needed in the 02J and the GL5 is actually BAD for them...

EDIT: After a little digging, I can't seem to back up my memory...

I was the same way. I bought it from a tdiclub vendor that recommended it for a gear oil change. I couldn't find much anti-gl5 info for the o2j. I know the gl5 is detrimental to yellow metals.

I still may change it and see if the problem persists.

 

[Smalls]

So I may have learned an expensive lesson here. I haven't gotten a chance to put it up on the lift yet, but I did throw the Malone Stg. 1 tune on it and took it for a test run.

The noise is very prominent now. I am unable to go full throttle under 2500 or so rpm as any lower and the clutch doesn't hold at all. If I roll into it, it's 90% okay but I'm picking up a little vibration/tingle.

I have a feeling the dmf has kicked the bucket along with the 267k mi clutch. I wanted to beef everything up anyway. My goal with the car is 450+ftlb of torque so off to fixmyvw.com and grab a stage 3 while I'm there I suppose

 

[HogWrangler]

So I may have learned an expensive lesson here. I haven't gotten a chance to put it up on the lift yet, but I did throw the Malone Stg. 1 tune on it and took it for a test run.

The noise is very prominent now. I am unable to go full throttle under 2500 or so rpm as any lower and the clutch doesn't hold at all. If I roll into it, it's 90% okay but I'm picking up a little vibration/tingle.

I have a feeling the dmf has kicked the bucket along with the 267k mi clutch. I wanted to beef everything up anyway. My goal with the car is 450+ftlb of torque so off to fixmyvw.com and grab a stage 3 while I'm there I suppose

South bend stage three is only rated for 425ftbl unless you get the drag clutch http://www.dxdracingclutches.com/listings.cfm

Check out the DC clutches at boraparts.com

http://shopping.boraparts.com/product_info.php?cPath=21_26_33_51&products_id=225

 

[Smalls]

South bend stage three is only rated for 425ftbl unless you get the drag clutch http://www.dxdracingclutches.com/listings.cfm

Check out the DC clutches at boraparts.com

http://shopping.boraparts.com/product_info.php?cPath=21_26_33_51&products_id=225

Good call. I need to do some research as to what's going to best suit my needs.