thumping noise on slow/tight turns

[Flipckyz4m]

Anyone experience this before with their m coupe? Only getting these thumping sounds turning 180 degrees in a parking lot setting. Car was aligned recently so that shouldn't be an issue.

[Huz-Z]

I had a similar problem years ago on my Z4 3.0si. While my car has a different steering rack than your car, I fixed it by tightening the bolts on the strut braces in the engine compartment. It’s worth a try on your M - just be careful not to over tighten. Someone here may have the proper torque for this.

[dc_wright]

Originally Posted by Flipckyz4m

Anyone experience this before with their m coupe? Only getting these thumping sounds turning 180 degrees in a parking lot setting. Car was aligned recently so that shouldn't be an issue.

Try backing in a circle clockwise and counter clockwise and see if you hear the thumping. If it's an issue with a control arm bushing this will accentuate the thumping significantly.

[StickMon]

Coming from the front or the back?
The LSD will grump and groan a bit, it's just doing what they do.

[ZAR4MC]

if its like a grinding kind of sound coming from the rear on tight left/right turns then its most likely the LS diff... I use to get grinding/binding sounds when taking tight turns just after starting up the car... If i drove a few miles for everything to warm up and then tried doing any tight turns, the sound would be faint or gone... i guess this was because by then the oil would have properly shot up everywhere and lubricated the diff after a few miles... This is how you can test if its the diff... Start the car up, drive it about half a mile and then drive around in tight circles, you should be able hear the sound... after that drive the car for a few miles; Highway is preferred to get everything all nice and lubricated then stop somewhere and try to do tight turns to see if you hear the sound... if the sound is no longer present after the highway run, then its definitely your diff...

I ended up rebuilding my diff with new timkin Bearings, seals and BMW oil with FM booster and now there's no more funny sounds..

I've experenced this on 3 M Cars : E86 M, E85 M and my brothers E46 M3 and i rebuilt all 3 diffs with new seals and bearings to resolve the issue.

Hope this helps, see my journal for more details..

[3002 tii]

What others said, if the sound is from the rear it’s most likely the diff. Uneven tires or alignment settings will probably make it worse. You can always throw in some friction modifier if it bothers you enough.

[racerbruce]

Originally Posted by Huz-Z

I had a similar problem years ago on my Z4 3.0si. While my car has a different steering rack than your car, I fixed it by tightening the bolts on the strut braces in the engine compartment. It’s worth a try on your M - just be careful not to over tighten. Someone here may have the proper torque for this.

My strut brace bolts were loose and were causing a similar errant noise.

[MinneapolisJeff]

Originally Posted by racerbruce

My strut brace bolts were loose and were causing a similar errant noise.

same; I torque'd one brace to 25 ft-lbs and my noise went away

[Huz-Z]

Originally Posted by jman1975

same; I torque'd one brace to 25 ft-lbs and my noise went away

I'm really hoping I'm right - not because I have a need to be right - but because its the cheapest and easiest issue for the OP to fix.

[Flipckyz4m]

Yes it's actually more of a grinding sound than thumping now that I recall. LSD argument makes a lot of sense although it sounded like it was coming from the front than back. But then again, i am sitting right on the rear axle so maybe it was coming from the rear. I'll try making some tight turns after car is fully warmed up. Thanks for the replies.

[Big Mexican Women]

if it's coming from the front it is most likely ball joints

[Flipckyz4m]

Update: applied some differential lubrication and the noise is mostly gone on tight turns. Cheap fix