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Whodunnit?

Greenmachine
11-02-09, 10:27
Or should that be - what's doing it?

Ok one for all you budding detectives out there - a mystery noise and what might be causing it.

The van's a 1.9 td, 140k miles and well serviced. I'm getting an occasional noise, it can last for a few miles or a day or so. I comes and goes. It was first apparent about 12 months ago! It's been absent for a month or so but came back yesterday - today it's gone again. It might be back tomorrow or it could be quiet for the next few months.

It's best described as sounding exactly like a cv joint on the way out. It's unlike a wheel bearing where it would get worse when you turn and there's more load on it. It gets worse under power and goes quiet when you lift off. It sounds as if it's on the passenger side and it's definitely at the front. It doesn't go quiet when you apply the brakes a bit while under power.

I've check wheelnuts, balljoints, suspension links, brake discs and pads and found nothing. The van was MOT's just before Christmas and only needed new anti roll bar drop links and they couldn't find anything else wrong with it that might cause the noise (which it wasn't making at the time). I was so fed up with the noise that I decided to swap the cv joint but being unable to decide whether it was an inner or an outer joint I just had a whole driveshaft fitted on the passenger side.

That made it quiet again - but now it's back, just the same.

I thought the gearbox might be on the way out so I drained the oil expecting to find some metal in it but it was clean, no tell-tale metallic tinge from ground up metal and no loose bits. Refilled it with fresh oil.

I'm thinking it could still be an inner joint on the drivers side but there's no play in the joint and the gaiters aren't split at all. I'm tempted to just ignore it until the noise is constant or I get a terminal failure but am I missing something really obvious here? This is a van I do 600-700 miles a week in, I do all the work on it myself and whatever it needs it gets because it needs to be utterly reliable (which it actually is). I'll attempt pretty well any job on anything 'cos I've got a good idea what I'm doing but this has me totally stumped.

I'd welcome any suggestions as to other things to check just for peace of mind or hear if anyone else has had a similar problem.

Ta.

boxey
11-02-09, 12:00
This sounds just like mine ive had my van for 4 years and its had the problem all that time.I only average about 3000 miles a year. My is a 2.5tdi on a p reg with around about the same mileage.The garage has checked the oil in the gear box to.
Got to ring the garage later as they was going to take the van out for a drive so will keep you in formed what they come back with.
boxey

mole
11-02-09, 12:07
I think i have the same kind of problem i get a reasonably loud humming noise at 70 mph in 5th and the same revs in different gears, goes away totally at 73 mph.
I was thinking gearbox but that works perfect and no different after oil change.
The funny thing is i have only noticed it since i have taken off the engine tray not sure its connected but if any ones got any ideas would be good

Does this sound anything similer to you?

Cheers Alex

96 1.9TD By the way

boxey
11-02-09, 12:17
mines at any speed and rotational so speeds up when the van speeds up and goes as quick as it comes

Greenmachine
11-02-09, 12:17
I think i have the same kind of problem i get a reasonably loud humming noise at 70 mph in 5th and the same revs in different gears, goes away totally at 73 mph.
I was thinking gearbox but that works perfect and no different after oil change.
The funny thing is i have only noticed it since i have taken off the engine tray not sure its connected but if any ones got any ideas would be good

Does this sound anything similer to you?

Cheers Alex

96 1.9TD By the way

Mine doesn't seem particularly speed related or gear related, it happens in any gear and at a variety of speeds - it might go quiet at 73mph but as I rarely go that fast I couldn't possibly comment. I:

I'm tending to think it's something related to the final drive - diff, driveshafts etc.

boxey
12-02-09, 07:06
My van is back from the garage and the noise has gone.Not that they did anthing it had just gone again.So just got to wait to the next time.:(:(
boxey

t4world
12-02-09, 07:31
Green machine - you are describing exactly what I had once on a mk2 Golf GTI.

It ended up being a fooked engine mount causing vibration at certain speed/revs.

JONESY
12-02-09, 09:15
Mines the same it like a clunk noise low down on passenger side.
doing my head in. i get it alll time now.
mot soon so they might find what it is.
Cheers JONESY

Greenmachine
12-02-09, 17:07
Quiet as a mouse today but if I get half an hour tonight I'll check the engine mounts as I'll be doing another 300 miles this weekend.

bullfrog
12-02-09, 22:27
I would suggest the diff may be worn. Even in oil they will drone.
Had it loads of land rovers and rovers so maybe VWs are the same in that way ???

mowerman80
13-02-09, 07:36
I seem to have the same problem to . Havent thought about it lately as it only seems to happen when im towing the caravan or the van is really loaded up and heavy. Get a low rumbeling ,knocking noise at about 60mph and the van shakes at the same time and ease off the throttle and it disapperes. only seems to happen in 5th gear going up a incline with my foot to the floor. I think it does do it in other gears but the when you put it into 4th gear the revs increase then its not so noticable, as i say it only happens mainly towing the caravan going up hill in 5th gear, flat roads and down hill with no power on is fine. Been meaning to get it looked at but its like looking for a needle in a haystack when it dont do it in normal driving conditions.

boxey
18-02-09, 20:23
all i can say it :* back has anyone fix theres