Passat B8 (MQB chassis) front suspension noise - disappears when wet!

[petemac110]

I'd be interested to hear the thoughts of other members re: front suspension noises that I've had on and off with my car, whether a Passat B8, or other MQB chassis cars (including Skodas!)

Shortly after purchasing the car about a year ago, I noticed that the front end was knocking and making a terrible racket over speedhumps and in and out of driveways etc. This was completely rectified via the VWAG 'factory fix' for the binding lower control arm bushes as per the TSB (i.e. appropriate grease in the slots where the bushes bind under load), along with careful application of Wurth HHS 5000 penetrating sticky lube on other bushes. It felt amazing!

Over the subsequent 9 months or so, I've noticed a rattle/knock from the passenger side front suspension at a particular point when cornering. It doesn't always occur - it's as though I need to be cornering at a particular speed, with a certain amount of steering lock, and the suspension loaded up a certain way.

It seems to knock less with the DCC set to sport (AKA stiff) which I've taken to mean that when the suspension has less movement/articulation, whatever is knocking is not able to move as much.

I've also noticed that the front end feels a bit 'stiff' in general. Hard to explain, but it's as though various rubber bushes are binding and not moving as freely as you'd hope. A visual inspection has revealed no obvious issues. The car generally feels a bit less agile, compliant and 'pointy' in the front end (not that the big land-yacht Passat is a particularly 'pointy' car to drive, of course!)

The plot thickens... when driving in the wet, the noise completely disappears and the front end feels MUCH nicer. The pointiness returns!

I'm taking this to mean one (or more) of three things:

a) once wet, any binding bushes move more freely and whatever is causing the knocking is now freed-up
b) whatever I lubed previously needs re-lubing
c) when driving in the wet, the tyres have inherently less grip, so this might result in the suspension/bushes not being loaded-up in the same way as when driving in the dry with full grip, (a long shot perhaps?)

The car has had a recent wheel alignment so I don't think there's an inherent alignment issue there.

I've read about people having issues with:

• Strut mounts and bearings (on the to-do list one day)
• Swaybar drop links (already replaced 5k ago - no change)
• Lower control arms (lubed as mentioned)
• Swaybar bushes (lubed)
• Noisy suspension level sensor arms/mechanisms (with good results where dealers have removed, lubed the ball sockets and re-fitted)
• Springs moving within the lower spring perch

I'll be servicing the car shortly and also changing all four rotors and pads, so I will check all of the above - with the suspension loaded and unloaded) and will see if I can identify the issue.

In the meantime... has anyone else had noisy front end issues that disappear when wet?

Any other personal experience with similar issues?

I may end up taking the car to a local Euro specialist (Pacortech or similar) but it's not in my DNA to hand the car over to someone unless to fix I'm absolutely stumped.

Thanks in advance!

[nermal]

I've had 2 suspension noise issues on my Arteon:

One was from your list - a (relatively) loose rear sway bar drop link, which made noise when going over bumps (especially while turning) - any twisting/flexing motion really. I crawled under the car and was able to turn one of the bolts ~2 turns - noise gone. I also had the sway bars and drop links replaced/upgraded, but one either wasn't fully tightened or worked itself a little loose.

The other was poor fitting brake pad(s), which also seemed to go away when wet. This was more of a clunky rattle noise, especially over bumps and ruts/pot-holes.. I first thought of lower control arm bushes, but a VW mechanic diagnosed it as the break pad (tested OEM pads and noise gone). Apparently, the Arteon takes a slightly longer pad and most aftermarket recommendations will rattle. There are also clips to prevent rattling that may not be set properly (or excess dust etc). I upgraded to big brakes and the front end became solid (all rattles gone).

Best of luck with it. I'm keen to find out what it ends up being.

[petemac110]

Thanks for the insights... greatly appreciated!

Now that you mention it, I do recall that when I fitted the (second-hand but as-new) ATE front pads and rotors from a written-off Passat, one of the clips wasn't perfect (possibly bent/damaged during removal from by the wrecker) and required some prising to make them fit OK. I had forgotten about that until now. It will be interesting to see if my replacement pads (TRW OEM super-dustmasters) will rectify the issue. We shall see!

[petemac110]

I've thrown on the new rotors and pads over the weekend, and had a good look around whilst under the car. I gave the control arm bushes a good clean and re-lube, hit the swaybar bushes and other control arm bushes with Wurth HHS5000, did as good a physical inspection as I could, checked for percieved excess play in bushes with leverage via a prybar... but the front end still feels rubbish at times.

I have only just noticed some perceived rumbling/friction from the front end when turning on concrete surfaces e.g car parks and the like. I haven't noticed it on asphalt... yet.

I'm nailing my flag to it being either the lower control arms, or the strut mounts and bearings.

I think a trip to Pacortech is on the cards... maybe I can hold out until November for the usual Black Friday 20% off specials on UGP reflashes and strategically kill two birds with one stone. The JB4's days could be numbered!

[nermal]

I wonder if it could be something simple like tire noise (badly worn tires) or a wheel alignment?

Our old 2008 125TDI Passat had bad tire noise that sounded like a thudding while driving down the road... I was sure there were major suspension issues... but it disappeared after replacing the near-new factory tires.

I've also had worn strut-mount bearings on the R36, but that mainly made it feel rubbish while turning at low speed (ie. parking).

Hope you get it sorted - keen to find out what it is.

[petemac110]

I wonder if it could be something simple like tire noise (badly worn tires) or a wheel alignment?

I've also had worn strut-mount bearings on the R36, but that mainly made it feel rubbish while turning at low speed (ie. parking).

Thanks mate - you and me both!

The tyres are only 8k old and have been recently rotated and balanced, along with a full wheel alignment, but there was no change to how the car feels.

I've heard of people giving the strut mounts and bearings a spray with either a lot of water, some WD-40 or silicon spray, to see if it results in smoother strut bearing operation and thus highlighting possible bearing or mount issues. I might give this a go at some stage, although I'm cautious about using WD-40 or silicon lube in case it drips down onto the tyres and brakes. Water might be the way to go - a solid spray followed by a drive straight away.

I'll chew in this a bit further before acting.

[curly747]

Maybe its a steering issue. Tie rod ? I have had knocking noise when cornering in an old car which turned out to be a tie rod.

[petemac110]

Maybe its a steering issue. Tie rod ? I have had knocking noise when cornering in an old car which turned out to be a tie rod.

i couldn’t detect any wheel bearing or steering/tie rod/ball joint movement - it all seems solid as a rock. I’ve had this kind of noise in a previous car and this sounds quite different. Nowhere near as intense.

I’ve been driving the car with the suspension set to ‘sport’ (the stiffest setting) and it’s been virtually silent. It really does seem that with the damping wound all the way up, it prevents the movement/articulation that allows the rattle or knock to occur.

[nermal]

i couldn’t detect any wheel bearing or steering/tie rod/ball joint movement - it all seems solid as a rock. I’ve had this kind of noise in a previous car and this sounds quite different. Nowhere near as intense.

I’ve been driving the car with the suspension set to ‘sport’ (the stiffest setting) and it’s been virtually silent. It really does seem that with the damping wound all the way up, it prevents the movement/articulation that allows the rattle or knock to occur.

Have you checked/replaced the brake pads yet? Mine rattled less in sport mode before I replaced them.

[petemac110]

Have you checked/replaced the brake pads yet? Mine rattled less in sport mode before I replaced them.

Yeah, I replaced the rotors and pads a few weeks ago as noted above. There was no change, and when I think about the kind of noise that I occasionally hear, it makes sense that it’s not brake-related.

This is the challenge with internet diagnosis I guess - a rattle, clunk, groan etc can mean so many different things to different people depending upon the intensity, frequency, duration, conditions under which they occur.