(Help needed) Bad knocking noise after change to winter tires.

[seb15243]

Hi,
I'm in need of help with my 2.0TDI 2006 Passat Estate... I bought it a month ago and been quite happy with it until now.
I put on my winter tires last night and during the first ride with them on today, as I came of the throttle, I heard a horrible knocking noise from somewhere around the front left side. This knocking noise accelerates as you go faster, every time I come of the throttle/ every time I just slightly touch the throttle it knocks. Pretty badly too. While rolling or accelerating normal, there are no sounds. What could this be caused of? The wheel nuts are tightened, but I will be taking the wheels off today for further investigation.. Might have to put on the summer wheels again to see if the knocking is still there, which I doubt it would be.....

The summer tires/rims are 19" and the winter tires/rims are 16", which is the standard size.
The car is 14 years old and the front suspension did make some noise (not knocking) when going over speed bumps etc. with the oversized SUMMER tires on but its way worse with the 16" rims on. This might be because the suspension is able to travel further up/down now. I guess some bushings and other bits need changing but it shouldn't cause this horrible knocking anyway.. I also have a negative chamber issue on the rear which caused pretty bad wear on the inside of the rear left tire when it was on the 19" wheels. I was hoping it wouldn't be that bad with the original sized wheels.

I can put my money on that it is not related to the engine/transmission as it was just fine with the 19" wheels on. The 16" wheels where just balanced too. The suspension isn't modified/monkied with at all, the car has been owned and used by an older lady until now.

Do you guys have any ideas what could cause this knocking? As mentioned over, it only appears when coming of the throttle or slightly touching it. SH#T!

[Crasher]

If a CV joint is worn it can suddenly start making noises if the car is jacked up due to the extreme angle it is taken to, it happens to us occasionally just doing an MOT or service and it is very difficult to explain the issue to the customer who is usually a member of the "ever since club"

[seb15243]

Really?
I`ve never heard of that before. Well ****. Thank you for answering, the only thing I find funny is that I`ve had the car up and down on a lift like 3 times already after I bought the car without it happening.

I guess its time to get the car up in the air (again) to go over all the bushings and other parts that need replacing, might as well do the oil pump balance shaft too since the car has done 191 thousand km`s without it failing yet. As its a BKP PD engine, I fear it will fail anytime while driving after reading about it after I bought the car. Would`ve probably never have bought this car if I knew about the issues with the 2.0 engine, EPB failing, Passat rust issues as well as steering column lock failing.

[Crasher]

I have given up asking myself why odd things happen, it is such a common occurrence that I just shrug it off and fix it rather than stress myself agonising over “why?” Your list of 2006>2008 3C (B6 if you must use such nomenclature) maladies is short of around a dozen other problems they are prone to. In 40 years of being a VAG grease monkey I have never seen such a bag of unreliable **** as the early 3C, they are an absolute dog.

[seb15243]

Yeah, I knew these cars had some classic fault (which all cars do), but I had no idea it would be that bad.
I figured out what that knocking noise was (sort of), after removing all 4 wheels, cleaning everything up, bending a few heatsheilds behind the brakes a little, before I put the wheels on in the dark, outside, 2℃ and horrible winds. Then as the test drive was up, the electronic parking brake failed, which required me to take of the rear left wheel (again) to manually reset the EPB....

After that I took the car for a little spin without the wheel-caps on (yes my winter rims are the ugly steel ones that requires wheel caps), the knocking was completely gone.
So im actually not sure what the knocking noise was. It could`ve been a ever so slightly loose wheel as one of the front right wheel bolts werent tight enough anymore, OR it couldve been a loose wheel cap (which ofc. would be very embarrassing), or possibly a heat sheild touching something. Either way, the knocking is gone.. For now..

I had the car up on a lift tonight to inspect the EPB motors, CV joints and the front supspension in general. The EPB motors look like new on the inside, so the problem is not there. The connectors were dry and nice too. Then i hooked up an multimeter to the EPB harness and got my mate to press the button inside the car. Nothing. So im guessing the switch is bad, luckily they are dirt cheap....

[philipharmes]

" So im guessing the switch is bad "

You are best off getting a code read of the EPB problem with VCDS or equivalent.

I've had Controller failure, EPB motor failure & caliper splines strip, but never had a switch go wrong.

[Crasher]

Early 3C parking brake ECU’s are very fragile and temperamental, RossTec the producers of VCDS even put an ECU protecting feature in like they did with Golf 4 air bag ECU’s as even asking them to do something in output tests can fry them. Testing with the calipers disconnected can overheat the output stage and again, kill the ECU. Having said the the “control head” (AKA switch) as it is known is very failure prone but you should not do ANY work on this system without a suitable diagnostic system such as VCDS. Another of the ECU’s clever tricks is to change its own soft coding which makes it act incorrectly... this is becoming an increasing trend, the other week I had a T5 where the dash decided to recode itself for a Tachograph which shut down the speedo, blanked the trip and odometer and made the fuel gauge bounce about. It would not recode back and had to be replaced.

[seb15243]

Wow!

I`ve read and heard about the switch failing multiple times/at least the problem was solved after the switch was changed.
Why didn`t VW just use regular handbrakes.... at least until they would actually get them to work.. xd

Anyways, thanks guys... I havent even dared to plug in an obd2 scanner yet because im afraid all hell will show up on the screen :P

[Crasher]

They used electric parking brakes because apparently that is what the costumer wanted... to me just another step to autonomous driving and being killed by computer.

[seb15243]

Totally agree. My biggest concern with the Passat is now mainly the oil pump balance shaft- and how long it will keep up before it goes. What do you think? I`m not even sure if its gear driven or chain driven, but there are no loose chain noises or anything else. The engine sounds basically like a tractor when its cold, especially if I`m having some revs and going lightly off the throttle. Worn camshaft perhaps? But I guess that`s fine for an old PD. If it lasts for another 3-4 months before I possibly upgrade to a Tiguan with the 2.0 CR engine which apparently does not suffer from this balance shaft issue its fine by me..
I also fear that the steering column lock in my Passat will start troubling at some point, although it sounds "happy" when I insert the weird chip they call "key" into the dashboard...
.. My father is getting a new Skoda Kodiaq so therefore I can get his 2012 Tiguan cheap. The Tiguan has treated him well and looks to be a solid car, although I really want a car with the bulletproof 1.9 TDI engine... Preferably in a Skoda Octavia. Hmm.....