Diagnosing weird sound from engine bay
 

The sound is a low level clatter. Audible when at idle and low rpm in first gear. I think it only becomes inaudible because it is drowned out by normal engine sounds. It occurs to me now that it could be a failing water pump bearing. Does this seem likely if there are no coolant leaks? My first theory was a chain tensioner..... do they make a noise if failing?

Heat shield?

Manual or Tip? If it's manual, when you're in 1st, obviously your clutch would be depressed. If that's the case, I'd also suspect the throwout bearing. Try pressing and releasing the clutch and see if the noise changes.

Possible I guess, but the sound doesn’t change with rpm as I think it would if it were a vibration. It sounds more like marbles in a coffee can, but not very loud or tinny sounding. I’d love to hear if these water pumps fail like this. Or chain tensioners. I think I had an old Alfa with a bad water pump that may have sounded vaguely like this. But it leaked coolant. Thank you for the suggestion.

It is a manual. The clutch has no bearing so to speak, on the sound. Sounds exactly the same whether in gear, clutch in or out, or neutral. Thank you for the thought tho. I appreciate it. Cheers.

Ah, I was under the impression it only did it in 1st.

"It sounds more like marbles in a coffee can" ... IMS

Has this happened to you? It would be awesome if the IMS gave warning signs like that. All I've heard that it goes with no warning.

What I've read is that maybe it makes a strange sound for a sec or two then kaboom!

That’s my understanding. Anyway, I had an LN IMS bearing installed 2 years ago.

I so appreciate all ideas tho, thank you.

Are you diagnosing this noise from the driver's seat? If so then you need to get out and check from the back. My first guess would be something with the exhaust. Heat shields are notorious for coming loose.

thanks. I does not seem tied to vibration tho. But yeah, I going to have put on a rack next week.

I also have this problem. The sound goes away at 1100 rpm. I thought it was because of the bad motor mount. Changed the mount, sound persist, but dang the handling is better. While changing the motor mount I am sure i found the real cause. The power steering. The slash tray was soaked wil ps fluid. The top of the motor is wet with ps fluid. I did not have the time to pull out the pump because it requires moving the ac compressor, not a big deal but I'm not up to it right now, maybe later this week. Car is a 2001 tiptronic with a swapped 3.2.

any update of your issue?

if still trying to find the sound, try to remove the engine cover access behind the seats and then find a plastic tube to use like a stethoscope while engine running. Try to listen to your water pump, various pulleys, AC compressor and alternator.
I eliminated several sounds from water pump, 2 pulleys and engine mount and now last one need to fix is my compressor but no time yet to do it. Currently I have around 107k on ODO.

As crazy as this sounds. Check the heat shields on the cats.They can rattle at certain RPM.Been there.

This is about his car, not my first wife. :eek:

You got it. Water pump. And thank you for the excellent pics. I decided I didn’t want to mess with bleeding the coolant system tho. My first estimate was $1000 to replace the pump. A bit shocking.

Thanks for posting the solution.

What's involved in bleeding the coolant system? Is difficult?

When I replaced my WP I raised the rear of the car as high as my stands would allow... opened the bleeder valve... added coolant... revved... added more coolant... revved... repeat until the coolant level is to specs.

I then left the valve open for a few more days, drove around, and keeping an eye on the coolant level. Closed the valve and all has been good since.

You getting ready to replace your WP?

Not planning on it anytime soon, but you never know. I was curious what's involved in it for when I have to. I want get as much info on these cars as I can. ;)

Just my 2 cents worth. If you get your hands on a Uview Airlift or equivalent, the vacuum of the coolant linesand refill of coolant is a piece of cake. I got mine from Princess Auto here in Canada for about $40.00. Makes the whole process very easy. You do need access to a compressor to run the device so maybe not for everyone.

If you’re local I can do it for $250 on labor. hehehe

sfkjeld and piper6909, not really hard to replace it and just follow what starter986 instruction on bleeding. That is how I did on bleeding.