SL/R230: help diagnosing new sound
01-17-2023, 07:52 PM
#1
Member
Thread Starter
help diagnosing new sound
I'm hearing a whining sound that follows engine rpm. It's not that loud but I've had my car for over 10 years and it's a significant change. The mic didn't pick it up that well but it sounds somewhat like alternator whine. Wondering if a pulley bearing is going bad or if I have an exhaust leak. Any thoughts?
I have an appointment with my indy but not for several days. Scanned for codes with the fox but didn't find anything relevant. It's most noticeable at low parking lot speeds and when coming to stop.
I have an appointment with my indy but not for several days. Scanned for codes with the fox but didn't find anything relevant. It's most noticeable at low parking lot speeds and when coming to stop.
01-18-2023, 02:37 AM
#2
Super Member
You have the second generation ABC system with the pulsation dampener mounted on the ABC pump rather than remotely, like ABC 1 cars. When the latter fails there's an obvious whine and vibration; if yours has failed the symptoms might be the same. It sure sounds like it, from the video.
Put your stethoscope on the pump if you can reach in there, and if you have one, and see what you can hear.
An easy way to eliminate the pulleys and pump is to ease off the tensioner, slip the belt off then run the engine. If it's the ABC pump then the whine will stop dead. Don't worry about the red warnings that come up, you can clear them later. You can also spin the pulleys and all other belt driven accessories then and listen and feel for dodgy bearings.
Put your stethoscope on the pump if you can reach in there, and if you have one, and see what you can hear.
An easy way to eliminate the pulleys and pump is to ease off the tensioner, slip the belt off then run the engine. If it's the ABC pump then the whine will stop dead. Don't worry about the red warnings that come up, you can clear them later. You can also spin the pulleys and all other belt driven accessories then and listen and feel for dodgy bearings.
01-18-2023, 06:45 PM
#3
Member
Thread Starter
Thanks Tom! I was able to get my indy sooner and they said the pulsation dampener had an internal malfunction. They replaced it for $907 in labor plus $460 for the part. Noise is gone. Probably not a good price and way higher than DIY but I can't DIY.
You have the second generation ABC system with the pulsation dampener mounted on the ABC pump rather than remotely, like ABC 1 cars. When the latter fails there's an obvious whine and vibration; if yours has failed the symptoms might be the same. It sure sounds like it, from the video.
Put your stethoscope on the pump if you can reach in there, and if you have one, and see what you can hear.
An easy way to eliminate the pulleys and pump is to ease off the tensioner, slip the belt off then run the engine. If it's the ABC pump then the whine will stop dead. Don't worry about the red warnings that come up, you can clear them later. You can also spin the pulleys and all other belt driven accessories then and listen and feel for dodgy bearings.
Put your stethoscope on the pump if you can reach in there, and if you have one, and see what you can hear.
An easy way to eliminate the pulleys and pump is to ease off the tensioner, slip the belt off then run the engine. If it's the ABC pump then the whine will stop dead. Don't worry about the red warnings that come up, you can clear them later. You can also spin the pulleys and all other belt driven accessories then and listen and feel for dodgy bearings.
01-22-2023, 05:06 PM
#4
Senior Member
Join Date: Aug 2017
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2007 SL550 & 2012 S550 4matic
Glad you solved the issue, wondering if the charges included environmental and shop supplies, coffee pastries,etc.? Seems like dealer pricing to me.
01-22-2023, 09:18 PM
#5
Member
Thread Starter
My indy isn't cheap but does seem very competent. They have a pleasant waiting area that I never use but I pay for 
They said they don't do the shifter replacement but they had someone that specialized in it in the past and would reach out to him for me. Seemed a little odd.
They said they don't do the shifter replacement but they had someone that specialized in it in the past and would reach out to him for me. Seemed a little odd.
