Loud clunking noise

[minesapasty]

I know where you are coming from, but at 110k miles, and how much these cars were new, you would think that they would be built to last a bit longer.

Someone else mentioned that it is strange why the mechanic couldn't pinpoint where the noise was coming from, but I drive the car everyday, and the noise seems to happen differently everyday. When it first happened, I went straight into his workshop, he checked everything, he opened the rear diff case, change the oil etc and the noise went and it was gone for days, he told me to drive it and see how it goes as he didn't believe that a diff fault would cause such a symptom....... and the noise returned (the day after I had settled the bill). I will set my phone to record with the window down, it should record it. My son was able to hear it while we were talking on the hands free, so obviously the phone microphone will detect the noise.

[andrewwynn]

I usually call the sway bar link s sound a tap vs. a clunk. On the E53 the usual culprit for a clunk sound is the tension strut but that will need repeatable from firm braking at slow speeds.

Tension strut aka lower control arm aka upper control arm aka I'm sure there are more. BMW calls it the tension strut. On e53 they have oil filled rubber bushing that tears apart at some point and you get a very distinct clunk when braking.

Back to the Morse Code tapping. Still sounds like what you described. Any difference in topography left to right side will push or pull on the sway bar link. When the rubber fails on the joint the grease comes out and they fail and the socket gets a little loose. A crap ton of force goes through the joint so it makes a pretty solid tap/clunk and it's frequent.

Only the top up joint I think you can do the tape trick so if the bottom joint is shot I don't think that will work though a hose clamp might.

If you can twist the link left and right by hand it's likely shot.

[Maruzo]

Hi Andrew, mine does not appear to have any crack or leak on both upper and lower rubber. I also tried to move it by hand and found it pretty much fixed in position.

I will replace both all the same since it doesn’t look that difficult of a job and it’s one less likely culprit eliminated.

But I am really worried that I’ll activate the air compressor when I jack it up again. Last time I did that the compressor came on and tried to lower the car as I was pushing it up with the jack.

I also seem to have a faulty FRM module after unplugging the battery!

[andrewwynn]

Originally Posted by Maruzo

Hi Andrew, mine does not appear to have any crack or leak on both upper and lower rubber. I also tried to move it by hand and found it pretty much fixed in position.



I will replace both all the same since it doesn’t look that difficult of a job and it’s one less likely culprit eliminated.



But I am really worried that I’ll activate the air compressor when I jack it up again. Last time I did that the compressor came on and tried to lower the car as I was pushing it up with the jack.



I also seem to have a faulty FRM module after unplugging the battery!

If your level sensors are working properly the self leveling system should deactivate when lifting off the ground. If you think about it when lifting the system would try to let air out to lower the car if you lift.

The rule with suspension joints is 19 times out of 20 you can't manipulate by hand to find loose joints. They make special 6' long testing bars you bolt onto the lug mounts to be able to test for loose ball joints. Once you can manipulate by hand they are long long gone.

I've replaced noisy sway bar links that didn't show wear they just taped Morse code. I was able to confirm with the tight tape wrap test but that only works on the top joint. I would try a hose clamp on the lower joint if it was suspect.

The noise is very distinct. I would be able to tell from a recording most likely. It will happen from very subtle road undulations and more noticeable at speeds closer to 15-20 mph.

[Maruzo]

Originally Posted by andrewwynn

If your level sensors are working properly the self leveling system should deactivate when lifting off the ground. If you think about it when lifting the system would try to let air out to lower the car if you lift.

The rule with suspension joints is 19 times out of 20 you can't manipulate by hand to find loose joints. They make special 6' long testing bars you bolt onto the lug mounts to be able to test for loose ball joints. Once you can manipulate by hand they are long long gone.

I've replaced noisy sway bar links that didn't show wear they just taped Morse code. I was able to confirm with the tight tape wrap test but that only works on the top joint. I would try a hose clamp on the lower joint if it was suspect.

The noise is very distinct. I would be able to tell from a recording most likely. It will happen from very subtle road undulations and more noticeable at speeds closer to 15-20 mph.

I agree with you as there's more tapping sound during lower speed city driving.

Interesting take on the air compressor letting air out therefore the car actually appears to lower as I jack up the car.

So this is normal? I should've just kept on jacking and not unplug the battery.

Now the FRM is shot and I'll have to find out if the dealership can honor the extended warranty on it.

[Maruzo]

Update:

After carefully listening to the noise again today while driving home, I remembered this noise was very similar to the rattles that I had experienced when I first acquired the E53 X5. That noise was identified to be the rattle from the loose rear trunk hatch latch.

The noise is more knocking knocking than tapping tapping, now that I had something to compare with from memory.

I decided to tape up all three latches on the E70's rear trunk hatch with cloth friction tape, same ones I used on the E53 per one of the forum member's suggestion (don't remember his name now, but thank you again for the valuable tip!)

Just test drove it again after the tape wrap on the latch, and the noise has considerably reduced.

The center latch is slightly loose and if I tape it more than once the trunk hatch will only open slightly.

If I wrap just a thin layer then the hatch will open fully without any issues.

But one layer doesn't seem to be enough, as I can still hear slight rattle from time to time.

Definitely a major improvement, and i hope my brain will get used to the slight rattle as I drive it more frequently.

Anyway sorry to hijack minesapasty's thread again, but hopefully my discovery could help others who may have the same rattle issue as me on their beloved E70.

Cheers!

p.s. sway bar link is a wear item so I'll be keeping the new parts once they arrive for their eventual replacement down the road.

[andrewwynn]

Unless I'm working on the air suspension, I've never pulled the fuse or disconnected the battery when jacking up the car. I've never had an issue with the air pump running during the lift or setting down.

[Maruzo]

Originally Posted by andrewwynn

Unless I'm working on the air suspension, I've never pulled the fuse or disconnected the battery when jacking up the car. I've never had an issue with the air pump running during the lift or setting down.

Good to know. Speaking of jacking up the car, the jack point is slightly ripped on the edge, probably due to improper tools. Are these jack points easy to replace? I found them on ebay for relatively cheap: https://www.ebay.com/itm/NEW-Under-C...72.m2749.l2649

Bought 2 and will attempt to replace my cracked front 2 units.

Do you just pry them loose or is there a screw that you have to deal with?

[Happy]

Originally Posted by Maruzo

Good to know. Speaking of jacking up the car, the jack point is slightly ripped on the edge, probably due to improper tools. Are these jack points easy to replace? I found them on ebay for relatively cheap: https://www.ebay.com/itm/NEW-Under-C...72.m2749.l2649

Bought 2 and will attempt to replace my cracked front 2 units.

Do you just pry them loose or is there a screw that you have to deal with?

Looks like the two outer tabs are tapered. They should pop out. Maybe some light prying.

[crystalworks]

Originally Posted by Maruzo

Good to know. Speaking of jacking up the car, the jack point is slightly ripped on the edge, probably due to improper tools. Are these jack points easy to replace? I found them on ebay for relatively cheap: https://www.ebay.com/itm/NEW-Under-C...72.m2749.l2649

Bought 2 and will attempt to replace my cracked front 2 units.

Do you just pry them loose or is there a screw that you have to deal with?

No screw. Just hit em with a hammer, or 3lb mini sledge (eliminates any possible resistance ). Pop the new ones in. What sucks is when someone screws up the jack points and then just lifts from the metal underneath... and bends it. Then you have to spend time with pry bars and the like to straighten it before putting the new lift points on. Been there on multiple bimmers.