Crankshaft play / movement
Thread Starter
Junior Member
Joined: Mar 2008
Posts: 37
Likes: 1
From: Pretoria, South Africa
2006 ML320Cdi Off Road Package; 2010 E500 Cab
Crankshaft play / movement
Hi
I have a very unusual problem. When idling my ML320cdi make a horrible screeching sound worse when cold, a little better when warm. When I drive off its mostly quiet but the moment I stop and the car is idling its back. I thought it was a tensioner pully or water pump. Since I did not have time to investigate or fix it myself I took it to my local dealership. They told me there is nothing wrong at the front of the engine the noise is coming from between the engine and gearbox. Since they quoted very high to remove and replace the gearbox I took the car to a well known Merc gearbox specialist whom replaced the TCM a year ago.
He guessed a broken or damaged flex plate when he heard the sound, but when he removed the gearbox he found nothing wrong.
He somehow determined that the noise is coming from the starter Bendix touching the flywheel due to sideways movement of the crankshaft!! He grabbed the flywheel and can feel movement and hear a clunking sound when pull and push it.
He suggested fitting spacers on the starter to move it a little further away from the flywheel which should temporary fix the problem.
Back ground info:
Merc told me the engine and gearbox mountings are very bad and need to be replaced asap.
The car has done 275000kms and is sometimes used for severe off-roading.
I have a performance chip.
The car is in great shape with full service history at the agents and no other problems.
I've owned it for six years since 135 000 kms
I cant think what is causing the crankshaft to move sideways, please help.
I have a very unusual problem. When idling my ML320cdi make a horrible screeching sound worse when cold, a little better when warm. When I drive off its mostly quiet but the moment I stop and the car is idling its back. I thought it was a tensioner pully or water pump. Since I did not have time to investigate or fix it myself I took it to my local dealership. They told me there is nothing wrong at the front of the engine the noise is coming from between the engine and gearbox. Since they quoted very high to remove and replace the gearbox I took the car to a well known Merc gearbox specialist whom replaced the TCM a year ago.
He guessed a broken or damaged flex plate when he heard the sound, but when he removed the gearbox he found nothing wrong.
He somehow determined that the noise is coming from the starter Bendix touching the flywheel due to sideways movement of the crankshaft!! He grabbed the flywheel and can feel movement and hear a clunking sound when pull and push it.
He suggested fitting spacers on the starter to move it a little further away from the flywheel which should temporary fix the problem.
Back ground info:
Merc told me the engine and gearbox mountings are very bad and need to be replaced asap.
The car has done 275000kms and is sometimes used for severe off-roading.
I have a performance chip.
The car is in great shape with full service history at the agents and no other problems.
I've owned it for six years since 135 000 kms
I cant think what is causing the crankshaft to move sideways, please help.
Super Member
Joined: Jun 2014
Posts: 507
Likes: 25
From: Massachusetts
2014 Smart ForTwo Passion Cabrio
No, it's not. 
With 170,000+ miles on that engine, I'd make an educated guess and say you need to rebuild that engine, or get a replacement, and do all the other items like engine mounts. Dundee will correct me if I am wrong, but that's my hunch from previous experience.
With 170,000+ miles on that engine, I'd make an educated guess and say you need to rebuild that engine, or get a replacement, and do all the other items like engine mounts. Dundee will correct me if I am wrong, but that's my hunch from previous experience.
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Joined: Oct 2011
Posts: 7,107
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From: Bronx, N.Y.
2002 ML 320 & 2006 ML500
Did you see him moving the flywheel?
When the car is idling, have you looked at the harmonic balancer to see if it is wobbling?
Last edited by Maj. Dundee; Jun 26, 2018 at 06:50 AM.
Thread Starter
Junior Member
Joined: Mar 2008
Posts: 37
Likes: 1
From: Pretoria, South Africa
2006 ML320Cdi Off Road Package; 2010 E500 Cab
Thanks for your reply, I do believe that these engins can easily do 500 000kms, 300 000miles without any problems.
Thread Starter
Junior Member
Joined: Mar 2008
Posts: 37
Likes: 1
From: Pretoria, South Africa
2006 ML320Cdi Off Road Package; 2010 E500 Cab
Thread Starter
Junior Member
Joined: Mar 2008
Posts: 37
Likes: 1
From: Pretoria, South Africa
2006 ML320Cdi Off Road Package; 2010 E500 Cab
I discussed this with various Merc people around here and everyone tell me the same story, It is unheard off that an Automatic Merc wear the thrust bearings.
With this in mind I traveled the 160kms to where the car is and back, to go see for myself.
He does not move the crankshaft by hand, he pull it back with a strongarm between the flex-plate and the block and then push it forward towards the front with his hands on the flex-plate, when he does this you can feel a very slight movement on the front crankshaft pully. I'm convinced this movement is normal.
He told me that the crank was just a wild guess as he cannot find anything else that can cause the noise.
There is no scratch marks anywhere in the bellhousing, not on the flex-plate, the torque convertor or anything else.
There is three places on the ring gear about evenly spread on thirds on the circumference where it is shiny and show some wear, this brought him to the conclusion that the starter is touching the ring gear causing the noise. He then took the starter to an auto electrician whom said it does show wear which is normal considering the cars high mileage but nothing that can cause the noise or justify replacement.
I asked him to put everything back together and use the washers as suggested and see, he did that and the noise is gone.
Here are links to a video with the noise and photos of the flex-plate and starter
Video with noise - https://www.dropbox.com/s/qhk7zea3ef...95929.mp4?dl=0
Photo of flex-plate - https://www.dropbox.com/s/montj1rkay...22129.jpg?dl=0
Photo of starter - https://www.dropbox.com/s/5ta7avm3h5...22200.jpg?dl=0
I think I'm going to replace the starter, its more likely to be the cause than the thrust-bearings and its old and worn anyway?
Also I'm still not convinced that its not the belt or one of the pulleys in front of the engine.
With this in mind I traveled the 160kms to where the car is and back, to go see for myself.
He does not move the crankshaft by hand, he pull it back with a strongarm between the flex-plate and the block and then push it forward towards the front with his hands on the flex-plate, when he does this you can feel a very slight movement on the front crankshaft pully. I'm convinced this movement is normal.
He told me that the crank was just a wild guess as he cannot find anything else that can cause the noise.
There is no scratch marks anywhere in the bellhousing, not on the flex-plate, the torque convertor or anything else.
There is three places on the ring gear about evenly spread on thirds on the circumference where it is shiny and show some wear, this brought him to the conclusion that the starter is touching the ring gear causing the noise. He then took the starter to an auto electrician whom said it does show wear which is normal considering the cars high mileage but nothing that can cause the noise or justify replacement.
I asked him to put everything back together and use the washers as suggested and see, he did that and the noise is gone.
Here are links to a video with the noise and photos of the flex-plate and starter
Video with noise - https://www.dropbox.com/s/qhk7zea3ef...95929.mp4?dl=0
Photo of flex-plate - https://www.dropbox.com/s/montj1rkay...22129.jpg?dl=0
Photo of starter - https://www.dropbox.com/s/5ta7avm3h5...22200.jpg?dl=0
I think I'm going to replace the starter, its more likely to be the cause than the thrust-bearings and its old and worn anyway?
Also I'm still not convinced that its not the belt or one of the pulleys in front of the engine.
Last edited by JohanSL; Jun 27, 2018 at 02:13 PM.
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From: Bronx, N.Y.
2002 ML 320 & 2006 ML500
Thread Starter
Junior Member
Joined: Mar 2008
Posts: 37
Likes: 1
From: Pretoria, South Africa
2006 ML320Cdi Off Road Package; 2010 E500 Cab
Thanks for the reply, I did answer you:
”He does not move the crankshaft by hand, he pull it back with a strongarm between the flex-plate and the block and then push it forward towards the front with his hands on the flex-plate, when he does this you can feel a very slight movement on the front crankshaft pully. I'm convinced this movement is normal”
”He does not move the crankshaft by hand, he pull it back with a strongarm between the flex-plate and the block and then push it forward towards the front with his hands on the flex-plate, when he does this you can feel a very slight movement on the front crankshaft pully. I'm convinced this movement is normal”
Thread Starter
Junior Member
Joined: Mar 2008
Posts: 37
Likes: 1
From: Pretoria, South Africa
2006 ML320Cdi Off Road Package; 2010 E500 Cab
The car is fine now, it was just the starter.
I took it to another auto electritian whom diagnosed it as a warn bush on the starter, he replaced the bush and the problem is gone!
Thanks for your advice.
I took it to another auto electritian whom diagnosed it as a warn bush on the starter, he replaced the bush and the problem is gone!
Thanks for your advice.
