Whining noise from Power Steering after driving for half an hour
Thread Starter
Newbie
Joined: Jan 2010
Posts: 2
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ML320
Whining noise from Power Steering after driving for half an hour
Hi Everyone,
My Power steering on 1999 ML320 is making noise but it starts only after I have driven for 20-30 mins. Initially when I start the engine, it is quiet but after car gets heated a bit, I can hear it not only on the turns but even when the steering wheel is in the middle position.
I have already changed the O-ring & have removed air from the system by turning the wheels (lock to lock) 50 times. I think my Power Steering system is taking air from some where as I checked the resovior & there was a bit of froth on the side. This was after the engine had cooled down a bit & fluid level in the resovior dropped a little so I am assuming there was some froth when the car was running.
I can't see any leak or power steering fluid on any hoses but I did replace the Power Steering fluid in the resovior with non Mercedes one. Could it be the fluid? Another thing worth mentioning is that I changed my radiator & when I put the hoses back, one of the hoses (not sure if it was high pressure or return) was not screwed properly so it leaked. I unscrewed & tightened it & can't see any leak since than so I am assuming it is fine but than my power steering had no noise before I changed the radiator so they could be related.
Any suggestions will be appreciated.
Best Regards
Atish
My Power steering on 1999 ML320 is making noise but it starts only after I have driven for 20-30 mins. Initially when I start the engine, it is quiet but after car gets heated a bit, I can hear it not only on the turns but even when the steering wheel is in the middle position.
I have already changed the O-ring & have removed air from the system by turning the wheels (lock to lock) 50 times. I think my Power Steering system is taking air from some where as I checked the resovior & there was a bit of froth on the side. This was after the engine had cooled down a bit & fluid level in the resovior dropped a little so I am assuming there was some froth when the car was running.
I can't see any leak or power steering fluid on any hoses but I did replace the Power Steering fluid in the resovior with non Mercedes one. Could it be the fluid? Another thing worth mentioning is that I changed my radiator & when I put the hoses back, one of the hoses (not sure if it was high pressure or return) was not screwed properly so it leaked. I unscrewed & tightened it & can't see any leak since than so I am assuming it is fine but than my power steering had no noise before I changed the radiator so they could be related.
Any suggestions will be appreciated.
Best Regards
Atish
Super Member
Joined: May 2009
Posts: 673
Likes: 27
From: Frederick
2000 ML320, 2005 E320 CDI
Well known and documented problem with the lower hose on the pump becoming disconnected and loose and letting air in system as well as leaking. MB Dealer should replace free of charge.
Thread Starter
Newbie
Joined: Jan 2010
Posts: 2
Likes: 0
ML320
Hi Boardboy,
Thanks for your reply however I checked the hose & it seems to be alright. Also the noise is only when, I have driven for 20-30 mins. Do you still think it should be the lower hose.
In terms of getting free replacement from the dealer, is the car supposed to be under warranty or would they do it as it is a documented problem?
Best Regards
Atish
Thanks for your reply however I checked the hose & it seems to be alright. Also the noise is only when, I have driven for 20-30 mins. Do you still think it should be the lower hose.
In terms of getting free replacement from the dealer, is the car supposed to be under warranty or would they do it as it is a documented problem?
Best Regards
Atish
Super Member
Joined: May 2009
Posts: 673
Likes: 27
From: Frederick
2000 ML320, 2005 E320 CDI
Well if you checked the hose...(and I am guessing you know what you are doing) then it may be air in the pump. I would check the lines again myself...just to make sure. After running 20 minutes and it makes the sound...that would mean to me...air getting in. I paid $160 for my pump...but others are saying they run $300 now. Either way...be ready for replacing your pump when you do find out what this is...worst case and all.
Take to a shop for a better diagnostic if you feel you are 100% sure about the hose. Personally I would take it to MB and ask about replacing the hose anyway...they also replaced my pump (no service charge, paid for only parts) because of it. Not saying this will happen for you - but worth a shot.
Take to a shop for a better diagnostic if you feel you are 100% sure about the hose. Personally I would take it to MB and ask about replacing the hose anyway...they also replaced my pump (no service charge, paid for only parts) because of it. Not saying this will happen for you - but worth a shot.
