Cold Weather Rattle from front end

[Bored of Audi]

oohh can't wait to see if you can get it at the very least diagnosed. Mine goes for its 1st service in 20 days

Good to turn up and tell them what the problem is.. Fingers crossed

[Walt White Coupe]

So a brief update. The car is still at the dealer. After two days the service manager says they can't reproduce the "rattle". They are also doing other maintenance tasks. Sort of what I expected. I've arranged to meet with the shop foreman tomorrow morning at 8 am with temps around 34 degrees F to take a test drive with him and hopefully I can make the car do it's "rattle". To be continued.

[Walt White Coupe]

So just back from the service dept. With temps in the mid 30's the noise was very subtle, I could hear it and a mile or so of driving the service foreman also could hear it. Just to refresh his memory I played the recorded sound clip thru the cars sound system from my phone. He said that they had already checked the front suspension for anything that was loose and didn't find anything abnormal. But to him the sound (and this is relying more the recording than the slight sound that he heard while driving) was indicative of worn sway bar links/bushings. So he's ordering those parts and will replace them on my next visit when they arrive in a few days. To be continued.

[Bored of Audi]

any update Walt?

[Walt White Coupe]

So I took the car in January 31st for final warranty maintenance, check rattle, loose seat, truck only opening partially. Warranty ends 3/15 so they didn't do the oil change and brake system flush. Told me it was not close enough to due date in March.

They ordered parts for possible cause of rattle, sway bar links and the other problems. Service manager told me to schedule next appointment for early March and they will do all the repairs and maintenance. So that's all scheduled for first week in March. Will update at that time.

[Bored of Audi]

Hi Walt,

You get anywhere ?

Edit, Sorry Walt did not read it correctly, wait and see come march !

[Bored of Audi]

mines been in for its first service nothing found...

[Walt White Coupe]

Mine will be back in the service dept in two and half weeks. At least we will find out if the cause of the noise is the "sway bar". If I had to guess that's where I'd look first.

[Bored of Audi]

hi Walt,

You motor been back in yet?

[ezmaass]

Every BMW I've owned has, at least over time, developed front suspension related noises - usually due to loose control arms (upper/lower) and bushings. In all of those cases, it was obvious when driving over any slightly bumpy surface - you'd usually hear a bit of rattle and there would be some play feeling coming through the wheel. I don't believe temperature ever affected it, though.

Even if it's NOT the problem, I've found that it's just good "BMW maintenance" to replace the control arms and bushings every so often, regardless. It brings back that "new car" ride in many cases. Couple it with some new shocks and tires around the 50k mark, and the car will feel like new.

My previous 550xi was the first BMW I had with variable dampers, but I only drove that car for about 19k miles before replacing it with the current 650xi GC. My R8 also has a similar technology (Audi calls it "magnetic ride"), but again I haven't put enough miles on it to ever replace shocks. Given that the Audi ones are super expensive (around $8k for all four), I wonder if the BMW VDC shocks are similarly expensive... in which case, I wouldn't arbitrarily replace them as preventative maintenance (as I described above).

[Walt White Coupe]

So the two major issues I had with the car when I brought it in for it's final 4 year manufacturer warranty service was the rattle in the front end in cold weather and a loose front seat.

For the loose front seat, they replaced the entire seat frame and transferred all the electric motors and seat covers/cushions from the old seat to the new frame. Not only did that solve the "looseness" but it softened the cushion on the seat bottom. I had complained previously that after about 4 to 5 hours in that seat, it felt like I was on a torture rack and bought an additional seat cushion to make it softer and it did. But now after this repair the seat is very comfortable without the extra cushion.



http://www.faulknerbmwpartssource.co...me-52107351859

For the front end rattle they replaced the sway bar end links. When I picked up the car the temps outside were ~60 degrees F so I knew the front end would not rattle. As luck would have it we've had some really cold mornings the last few days, 29 yesterday, 22 today. I was prepared to bring the car back if the "links" didn't solve the problem. But after driving the car on both mornings over a lot of different pavements it seems that the problem while not 100% solved is probably 95% fixed. All I can suspect is that even the new links have some play in them that is responsible for the 5% residual rattling. But it's so slight that most people would never hear it especially if you have the radio on or the windows open. So I'm gonna say for now that it was fixed as well.



http://www.ebay.com/itm/Genuine-BMW-...-/191890085832

[Bored of Audi]

Thanks for the reply Walt.

Let us know how you get on as it is strange that after a couple of miles there must be significant expansions to solve the issue. there must be significant heat to case such expansion.

Its getting warmer in the UK 14°C yesterday so my problem will probably not recur until winter, unless we get a sudden drop which is still possible.

Mind you when I get to Jan next year the hunt for a new machine will start as I never keep them over the warranty period !

Thanks once again.

David

[ezmaass]

Thanks for the update, Walt. As I said above, it's been my experience that suspensions are usually one of those areas that are ripe for a rebuild every few years - for some reason, especially with my BMWs. The good news is that it usually pays nice dividends in "like new" ride quality returning if you go all out on it. Glad to hear that your problems have largely been solved!

[Walt White Coupe]

Update: Sway bar links did not solve the "rattling" problem. Today with temps around 65 degrees it was back just like before but now in relatively warm weather. It did go away after the car warmed up. So now I'm convinced it's something directly attached to the motor but no idea what.

[upstate650]

Originally Posted by Walt White Coupe

Update: Sway bar links did not solve the "rattling" problem. Today with temps around 65 degrees it was back just like before but now in relatively warm weather. It did go away after the car warmed up. So now I'm convinced it's something directly attached to the motor but no idea what.

try replacing your downpipes with catless ones - it may solve the problem, it may not, but either way, you wont hear the rattle anymore.

[nealsil]

Originally Posted by Walt White Coupe

Update: Sway bar links did not solve the "rattling" problem. Today with temps around 65 degrees it was back just like before but now in relatively warm weather. It did go away after the car warmed up. So now I'm convinced it's something directly attached to the motor but no idea what.

Just an FYI update: no noise since replacing left front strut. Jury still out as warm weather is now in the NE.

[Bored of Audi]

Originally Posted by Walt White Coupe

Update: Sway bar links did not solve the "rattling" problem. Today with temps around 65 degrees it was back just like before but now in relatively warm weather. It did go away after the car warmed up. So now I'm convinced it's something directly attached to the motor but no idea what.

We had a drop in the uk near freezing again from 20+°C. and guess what it came back with vengeance...

[Bored of Audi]

Hi Walt,

I wonder if you ever got anywhere with this, its fast approaching winter in the UK and my 640 has started again with he knocking for at least the fist 2-3 miles !

[Walt White Coupe]

David,

The temps here have also started to drop. This morning it was 50 F and the rattle is back just like before. Mine also goes away as the engine heats up so I'm just going to 'try' and ignore it and turn up the radio. Like others, it just doesn't seem like the effort to track it down is worth the trouble. If anyone else figures it out, please post your solution.

[Bored of Audi]

I agree with you ... mine goes back to the lease company next October so it will be there problems to deal with !

Originally Posted by Walt White Coupe

David,

The temps here have also started to drop. This morning it was 50 F and the rattle is back just like before. Mine also goes away as the engine heats up so I'm just going to 'try' and ignore it and turn up the radio. Like others, it just doesn't seem like the effort to track it down is worth the trouble. If anyone else figures it out, please post your solution.

[Walt White Coupe]

I recently bought a "Carly" fault code reader. So I was playing around with it and one of the features is the ability to control the exhaust flappers at the end of the tailpipe while the reader is attached to the diagnostic port. So I cycled it back and forth, took a short ride with the flaps open just to see how it sounded.

So this morning it's 32 deg F outside and car has been sitting overnight and I take a ride to the store. Now I would expect the 'rattle' to happen. The car was quiet as a mouse, no rattle at all and the entire car seemed 'smoother' than ever before.

We that have had this rattle have been pretty sure it was coming from the front end and it sounded like it was coming from the suspension but it goes away as the car heats up. But that never made much sense because the suspension is not going to be that affected by engine heat in the short amount of time it takes for the rattle to go away. But the 'flapper' valves see engine heat pretty quickly and if they were the source of the rattle, the sound could be transmitted along the exhaust pipe to the hard connection at the engine and could sound like it's coming from there.

So right now I'm thinking that maybe 'cycling' the flappers did something that reset them and whatever that was, stopped them from rattling. I'll update as I drive the car more on cold mornings.

[Bored of Audi]

Now thats interesting .... I wonder when the flappers should operate etc ie I am no mechanic and just thin king about purpose !

Originally Posted by Walt White Coupe

I recently bought a "Carly" fault code reader. So I was playing around with it and one of the features is the ability to control the exhaust flappers at the end of the tailpipe while the reader is attached to the diagnostic port. So I cycled it back and forth, took a short ride with the flaps open just to see how it sounded.

So this morning it's 32 deg F outside and car has been sitting overnight and I take a ride to the store. Now I would expect the 'rattle' to happen. The car was quiet as a mouse, no rattle at all and the entire car seemed 'smoother' than ever before.

We that have had this rattle have been pretty sure it was coming from the front end and it sounded like it was coming from the suspension but it goes away as the car heats up. But that never made much sense because the suspension is not going to be that affected by engine heat in the short amount of time it takes for the rattle to go away. But the 'flapper' valves see engine heat pretty quickly and if they were the source of the rattle, the sound could be transmitted along the exhaust pipe to the hard connection at the engine and could sound like it's coming from there.

So right now I'm thinking that maybe 'cycling' the flappers did something that reset them and whatever that was, stopped them from rattling. I'll update as I drive the car more on cold mornings.