horible clunking grinding noise only in rain!?

[jack.s]

horrible clunking grinding noise only in rain!? does anybody know why my car might make these horrible sounds but only in the rain has not been a problem last few months as it is summer but with this heavy rain it seems to do this when there is lots of standing water?

 

[IIIadidasboy]

Stupid question, but do you have your wipers on - could it be something to do with them?

 

[inS4ne]

Can you give a vague area of where the noise is eminating from at all?

 

[jack.s]

its defenatly not the wipers lol it doesent happen on acceleration only in gear when slowing down letting off, its coming from underneath hard to say were but if i had to say it would be the front to middle you can feel in through the car to? seems like something to do with the drive system any ideas?:thumbsup:

 

[inS4ne]

You got a quattro AWD?

I'm finding it really hard to fathom how the difference between wet and dry could cause such a problem as you describe and under the conditions you describe????

Is it when you brake?

 

[jack.s]

yea it is a quattro i know its really odd it never happens in the dry and its really not nice when it does happen seems like something big is wrong! no its definatly not when breaking.

 

[jesters3]

Hmm, sounds similar to what I have had occasionaly... does it sound like something metallic is caught and getting spun round hence the grinding sound? I have looked all under the car, checked the brake area, CV Joints, Springs, ARB, heatshields and nothing. Only thing that i think it is related too is either Gearbox or Driveshaft., but there is no way in checking without ripping it apart. If I ever find out I will let you know.

 

[IIIadidasboy]

........ Only thing that i think it is related too is either Gearbox or Driveshaft.......

Was thinking about it last night whilst driving round my mates house (in the rain) and I started to wonder if it was Haldex related - as in maybe the rears coming into play more in the wet??

BUT, I'm certainly no Haldex specialist so I don't know how viable that explanation is, it was just a thought?

 

[inS4ne]

I think ^^^^^^^^ may have a valid point although cannot be for certain. If your rears are coming into play more than the fronts or indeed vica versa, it could cause some slip in the diff.

As already stated by someone though, you ain't never gonna know unless it's stripped apart. If it is and a nice loada metal filings are found, you'll know for sure

 

[Trick]

I have experienced a similar problem, when in the heavy rain you pass/splash through some standing water I get a really heavy vibration and noise that lasts for mabey 30 - 60 seconds, really loud and sounds as though the exhaust is vibrating the underside of the car. First time I heard it I shat myself and thought the car was ******. Seems to come from right under the drivers seat(ish).

 

[Boxxer1973]

had a similar problem years ago and it was literaly the exhaust contracting quickly as it cooled because of the big puddles check your hangars that the exhaus isnt too close to the body and is ligned straight could be touching the driveshaft

 

[jack.s]

yea thats sound exactly like what happens trick, big puddles 30-60 seconds sounds about right and yes i did too think my car was ****** the first time lol, but now you and boxer has said about the exhaust i really am starting to think it may be that as it only happens when lots of standing water and i must say i have though that a few times and it does sound like it could well be. cheers for the help guys i am feeling slightly relived in a way lol.

 

[IIIadidasboy]

Hopefully that'll be it then Jack - new exhaust and/or hangers will be a lot cheaper!!!

 

[jack.s]

yea its completely normal since the rain has gone, will have to check out those hangers! not changing the exhaust lol new turbo back already on there.

 

[Boxxer1973]

has it only been doing it since you had the exhaust?

 

[mramcha]

I used to have this happen a lot whne my S3 was new (2001). Every time I went through a big puddle, I'd get a horrible groaning clunking noise. I believe it was in fact the exhaust cooling rapidly and perhaps even knocking the underside of the car in the process.

Stopped happening as the car got older.

 

[jack.s]

yea only since the new one has been on there.

 

[jack.s]

seems a good explanation!

 

[bikenut55]

I've had this happen for the second or third time to me this evening on my S3. I'm fairly certain it is not related to the exhaust cooling and contracting (not in my case anyway).

It happens when there is a light to medium load placed into the drive system - either increasing speed, maintaining a constant speed up a hill or slowing down using engine breaking. If I raise the engine revs while in neutral there is no noise, put it back into gear and increase speed, the clunking noise comes back. Also, under heavy acceleration, the noise is slightly quieter.

What does confuse me is that it will stop for maybe 10 minutes and then come back again, often triggered by a bump in the road. I'm fairly certain that the noise is coming from the rear of the car but it is difficult to pinpoint which has been said above.

I'm leaning towards a CV or UJ somewhere but I don't know the car well to say much more. It's going in for a service and cambelt change in the next couple of weeks so I will ask the mechanic to have a look and let you know if I figure out any more.

 

[bikenut55]

A bit of a development on the strange noise - it appears to be something to do with a boost hose.

I had the car serviced with a cambelt change and all associated pumps and tensioners, plus I asked the mechanic to have a look over to see if he could see any thing that might cause the noise.

The next day when driving down the motorway in the rain, it was back but as I was slowing and speeding up in 6th I managed to blow a boost hose off. Once this was fixed, it wouldn't happen any more, and hasn't happened for a few weeks since, despite following a lorry to catch the spray in very heavy rain (a sure way to start it in th past).

How the boost hose causes the noise, I'm not sure, but it was happening a few seconds before the hose blew and it won't happen since it's been fixed. It's the only variation so it must be related.

Hope that helps.

 

[Danny Cawsey]

ive got this noise and found out its the abs sensor on its last legs, try pulling the abs fuse out and see if it still makes the noise.

 

[huntface]

Sorry to drag up a very old thread, but this happened to me this morning. Drove through a puddle and suddenly a horrible grinding and shaking through the car and underneath.

It sounded like it was coming from the front wheels, so could be a cv. However the rumble under the car made me think its something to do with the diff.

It went after a bit and was fine for the rest of my journey to work. I couldn't see anything obvious when I got to work.

I did have some work replacing the downpipe not so long ago, so could be something along the lines of bikcenut55's issues.

Any other thoughts?

 

[Bradderz_1988]

Do you have a milltek fitted ??

My B5 quattro used to do something like this and sounded horrible like a really bad wheel bearing turned out that when driving through standing water the exhaust would cool down dramatically and cause the exhaust to deform in shape and catch the diff carrier.

 

[huntface]

To be honest Bradderz I'm not sure. I would have thought they'd have just stuck a standard one on. I'll check the bill when I get home.

But yes that's the sound exactly, like a wheel bearing or stuck on brake calliper with no pad left! I thought I'd killed it. Switched the car off for a minute then drove off with no problems at all.