BMW M5 Forum and M6 Forums banner

1 - 20 of 20 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
I have a 2008 M5 with 2,700 miles on it. Every since I got the car there has been a thunking noise coming from the rear when driving over small bumps at speeds less than 40mph. The noise is a higher pitched thunk than the normal noise one hears from the suspension going up and down. the noise can be heard on the way "up" and down" but separate from the suspension travel noise.

The car has been at the dealer for more than two weeks. They have replaced shocks; shock mounts; found the gas tank not securely attached (so they corrected it and refoamed around it); corrected the location of the gas filler tube neck (foaming around that too); they found the rear axle carrier businbg mounting sleeve not sitting flush on body of vehicle so they addressed that; they have removed all interior trunk trim, battery, and flat tile repair components; and they have loosened and retorqued all rear suspension components. Noise still exists.

This is my third M5 and have had a 2006 550 too. I have driven multiple late model 5 series loaner cars - all sound tight like a BMW should - except this M5.

Anyone have any similar problems or any ideas? thanks for your help.:confused:
 

·
Premium Member
Joined
·
2,217 Posts
wow man.. thats a lot of wrong for a car so new. :eek:h:
 

·
Premium Member
Joined
·
2,217 Posts
 

·
Registered
Joined
·
8,300 Posts
To bad...sorry man...ya know it could be really SO many things, really too hard to diagnose here...they must keep looking...my buddy had a new Corvette that was built before a union strike..someone on the assembly line suspended a bottle from a wire in between a body panel and a frame rail, wow it took months to find it.....sorry
 
  • Like
Reactions: trol

·
Registered
Joined
·
8,300 Posts
To bad...sorry man...ya know it could be really SO many things, really too hard to diagnose here...they must keep looking...my buddy had a new Corvette that was built before a union strike..someone on the assembly line suspended a bottle from a wire in between a body panel and a frame rail, wow it took months to find it.....sorry
 
  • Like
Reactions: trol

·
Registered
Joined
·
8,300 Posts
Too bad...sorry man...ya know it could be really SO many things, really too hard to diagnose here...they must keep looking...my buddy had a new Corvette that was built before a union strike..someone on the assembly line suspended a bottle from a wire in between a body panel and a frame rail, wow it took months to find it.....sorry
 
  • Like
Reactions: trol

·
Registered
Joined
·
250 Posts
I had the same problem...It is coming from the differential...Take the car to the dealer and tell them to change the oil...It is the wrong oil..
 

·
Registered
Joined
·
4,246 Posts
My opinion is that it has to be something stupid to be overlooked. I would try looking more at the sway bar, brackets, links, bushings, subframe. It would be connected to suspension, but not direct5ly to actualy shocks or up and down motion and would be heard at low speed. Best of luck with your issues, hopefully they can remedy them and please do keep us updated.
 
  • Like
Reactions: unfoundhorsepower

·
Registered
Joined
·
693 Posts
I had the same problem...It is coming from the differential...Take the car to the dealer and tell them to change the oil...It is the wrong oil..
Why would the diff make a noise when going over small bumps??
I have what I think to be a similar noise on the right rear of the car.
It sounds to me like a weak shock.
 
  • Like
Reactions: unfoundhorsepower

·
Registered
Joined
·
5 Posts
Discussion Starter · #10 ·
UPDATE: Car was in the shop for 3 more days and then returned to me again. They had loosened and re-tightened all rear suspension components. Noise is still there - no change. they had the audacity to tell me the noise is "not abnormal". I will try to have oil in the differential changed next.
 

·
Registered
Joined
·
241 Posts
re:

check a few things...i had a problem with mine thumping and we found it was a defective rear arm rest(something with the bracket). they had to replace it but it was absolutely driving me nuts. i thought it was the rear dash but it was the arm rest...now i have a lovely sunroof rattle--
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #12 ·
UPDATE: spoke with BMW dealer again. They changed the differential oil at the 1,200 mile service. Noise was there before the change, and after, so that' s not the problem. ACHHHHHHHHH!
 

·
Registered
Joined
·
1,428 Posts
Thunks & rattles

Has the service tech driven the car using a hearing ear (microphone diagnostic tool?) Have they checked the exhaust system and springs?

After having a Dinan Stage 2 suspension installed, mine spent > 1 month in the shop diagnosing a low pitch thunk and high pitched rattle. The former was misassembled Dinan springs, no rubber coating, and the latter loose exhaust hangers.

While I assume your M is stock, the factory pieces could be installed wrong. The noises you mention sound familar.
 

·
Registered
Joined
·
693 Posts
I have a 2008 M5 with 2,700 miles on it. Every since I got the car there has been a thunking noise coming from the rear when driving over small bumps at speeds less than 40mph. The noise is a higher pitched thunk than the normal noise one hears from the suspension going up and down. the noise can be heard on the way "up" and down" but separate from the suspension travel noise.

The car has been at the dealer for more than two weeks. They have replaced shocks; shock mounts; found the gas tank not securely attached (so they corrected it and refoamed around it); corrected the location of the gas filler tube neck (foaming around that too); they found the rear axle carrier businbg mounting sleeve not sitting flush on body of vehicle so they addressed that; they have removed all interior trunk trim, battery, and flat tile repair components; and they have loosened and retorqued all rear suspension components. Noise still exists.

This is my third M5 and have had a 2006 550 too. I have driven multiple late model 5 series loaner cars - all sound tight like a BMW should - except this M5.

Anyone have any similar problems or any ideas? thanks for your help.:confused:
I am blown away that these cars coming out of Germany have so many poor connections/fittings!
Seems like quality control is slipping to the American way.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #16 ·
UPDATE: noise partially gone?

Back to the dealer again. This time assigned to their "rear suspension specialist". He felt noise was coming from the spring (where it hits some "rubber"). He said he had to readjust the spring so that it "seated differently".

I don't really understand how this could be the cause of the noise, for I assume that a spring is always under compression and my noise occurs both on the way up, and down, when I go over a bump. Nonetheless, he got a bit over 50% of the noise to go away (either not as frequent or not as loud).

Anyone have an ideas what this problem could be and can explain it better or have other thoughts?
thanks
 

·
Registered
Joined
·
1,010 Posts
I had some strange noises from the rear, dealer said it was normal. It was quite quiet and you could only hear it at slow speed over a rough surface.

I just had H&R springs installed and it is now as quiet as anything, just like a new car.
 

·
Registered
Joined
·
994 Posts
Good luck man. At east it sounds like your dealer is at least *trying* to help. I really hope they wake up actually figure out how to fix it. Darn stealers...:grrrrr:
 

·
Registered
Joined
·
2,881 Posts
any updates??
 

·
Registered
Joined
·
1,428 Posts
Back to the dealer again. This time assigned to their "rear suspension specialist". He felt noise was coming from the spring (where it hits some "rubber"). He said he had to readjust the spring so that it "seated differently".

I don't really understand how this could be the cause of the noise, for I assume that a spring is always under compression and my noise occurs both on the way up, and down, when I go over a bump. Nonetheless, he got a bit over 50% of the noise to go away (either not as frequent or not as loud).

Anyone have an ideas what this problem could be and can explain it better or have other thoughts?
thanks
If 50% of the noise went away by readjusting the spring seating, have them adjust it again. They are under compression but move around, especially on bumpy roads. If one is off center, it could be contacting the side of the bracket instead of in the middle.

Have they checked positioning and integrity of all brackets, links, bushings and sway bars? Does a heavy trunk load reduce the noise?

If they haven't used a microphone find another dealership.
 
1 - 20 of 20 Posts
Top