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View Full Version : mk4 gt tdi 130 turbo hissing noise - wastegate?



leemasiuk
06-04-2007, 12:34 PM
Hi people,

I'm in need of some help and advise and hope you can help.

my 51 plate golf mk4 GT TDI 130 has started making a hissing noise when i accelerate. A couple of months ago the MAF sensor was replaced as the car was running real slow. Once the MAF was replaced the power can back and everything seemed fine.

But now I’ve noticed this hissing noise which starts when accelerating. If I drive real slow blow 2000 revs I cant hear the noise. Any more revs and the hissing starts, drop the revs and it goes.

Someone has told me it could be the wastegate valve on the turbo? I#Does this sound right?

I’m not sure where is best to take my car to be diagnosed. I hope you can help.:confused:

Thanks

Lee

mkpp786
07-04-2007, 01:54 AM
unless ive misunderstood the question, I am pretty sure this is just the car taking in more air... mine does it too... there was a similar thread about this a few weeks ago.

Theres nothing to worry about!! and its normal for a diesel to do this!

Few months back i replaced my MAF too - and the (beautifull) "hissing" sound was increased compared to before it was replaced.

Hope this helps!

leemasiuk
07-04-2007, 12:31 PM
thanks for the reply.

sorry the question doesnt explain well enough.

I really dont think this is a normal sound, as it has only started in the last week. The hissing is quite load when i accelerate hard. like compressed air being released. you can easily hear it with the windows closed. Sometimes it seems louder.

i wonder if a loose/split hose/pipe could casue this. but i dont really know where to start looking? Any suggestions?

the performance seems a little down too (not a much boost on acelerating) and also the mpg seems to be worse than normal.

If this is normal, i dont understand why it has not made this noise before?

hope this helps to explain a little better

adamss24
07-04-2007, 01:22 PM
thanks for the reply.

sorry the question doesnt explain well enough.

I really dont think this is a normal sound, as it has only started in the last week. The hissing is quite load when i accelerate hard. like compressed air being released. you can easily hear it with the windows closed. Sometimes it seems louder.

i wonder if a loose/split hose/pipe could casue this. but i dont really know where to start looking? Any suggestions?

the performance seems a little down too (not a much boost on acelerating) and also the mpg seems to be worse than normal.

If this is normal, i dont understand why it has not made this noise before?

hope this helps to explain a little better
Check the boost pipes for leaks...tighten everything that looks or seems loose.You have faults stored in the memmory that will need erasing. All should get back to normal after that. Hope this helps.

leemasiuk
07-04-2007, 04:03 PM
Check the boost pipes for leaks...tighten everything that looks or seems loose.You have faults stored in the memmory that will need erasing. All should get back to normal after that. Hope this helps.

thanks for that. i intend to check for loose pipes and splits etc.

only thing is i am pretty much a novice with my car (mk4 gt tdi 130). i dont know where the boost pipes are located. whats the best way to find out what pipes i should be checking?

Alun
07-04-2007, 06:12 PM
Is the car fitted with an intercooler? If it has then you've probably got a split/corroded pipe going to/from the intercooler.

moff
10-04-2007, 08:45 AM
mine does it on my golf to but i just thoughtit was just my turbo whinding up then when i lef the revs off and change gear i can hear air being let out like a dump valve

Eshrules
10-04-2007, 11:58 AM
i suspect there may be a little confusion here between the 'normal' turbo sounds and the sound of a split hose....

if you can hear the noise from around 1700rpm to around 3000rpm (by which time the noise of the engine will mask it)...then i would suggest that it is probably just the turbo doing its job, ie sucking in the extra air it is there for. if you accelerate harshly and gear change quickly, you will notice a slight hiss, this is the wastegate doing its job also and releasing the excess boost pressure.

however if the 'hiss' is a constant noise and doesnt appear to alter with the revs of the engine through the gears, that to me would suggest a leak.

the turbo noise will tend to increase with the more gas you give the car...

also, if you have a boost leak, you will notice a severe lack in boost pressure and your car would probably lag around 400/500 rpm more than usual.

dipteshr
10-04-2007, 12:34 PM
i just changed my MAF sensor 2 weeks ago - the engine started performing as usual (back to normal torque) recently, i found that the turbo doesnt have that punch anymore. i can still hear it, and feel it in second and third gear, but not in first... any ideas?

leemasiuk
10-04-2007, 09:04 PM
hi,

thanks for the info everyone.

I still havn't found the cause. Think i'll have to bite the bullet and take it to a garage to check over.

The hissing is related to the RPM of the car but i am still sure it is not a standard turbo noise. I have had the car about 5months now and havent noticed any significant turbo noise, until now.

now as i accelerate hard the hissing starts and increases as i increase the gas. It is a very noticable sound, like compressed air being released. It begins at around 1700 rpm (matching the turbo) and increases as the RPM increases.

what are the symptoms of a sticking waste gate? as i have been told it could be this causing the problem:confused:

the revs do seem to be holding back and the performance seems to have dropped a little too, along with the mpg. I'm driving at low revs most of the time to avoid pushing the car, as i dont think its normal.

I am worried that driving the car may cause futher problems. A service is due in a few months and the display has been indicating this, currently stating 1300 miles to service

any more tips would be great :beerchug:

sugs04
11-04-2007, 11:11 PM
I'm pretty sure mine makes this noise you describe and I just put it down to the turbo doing it's job. Let me know if you find anything.

I'm going to get it inspection checked next month as it's still in warranty and I'll mention it then and see what VW say.

sugs

Lightweight
16-04-2007, 07:40 PM
Hi there, did you moanage to get your problem sorted? Would be well interested to hear if you found anything as i'm currently going experienceing a very similar problem.

I've got a 2003 golf TDI which i've had a for 3 months and its got about 75k on it. Was driving home the other day down the A34 and all of a sudden there was a loss of power (been no deterioration over time) and high pressure hiss (as you describe) when you put your foot down. i spoke to a mate who had a diesel passat and he said it might a be a blockage causing the the turbo to dump out of the wastegate. I've had to drive it today back and forth to work and its still doing it. My drive is about 30 miles on the motorway and the car's completely gutless! As you put your foot down there's the hiss and the accceleration is well down, as you back off the hiss dissapears. After about 20 minutes this morning the hissing stopped no matter what i did, but the performance was still well down.

I really nursed the car home tonight (minimal accleration, tried to keep below 2000rpm as much as possible) and the hiss was there all the way home when i pressed a bit too hard. Its booked in for a diagnostic on wednesday morning but am wondering what to expect.

Cheers

guyg
16-04-2007, 10:34 PM
Sounds like an air leak to me...

My130PD had a retaining lug on the turbo pipe from the intercooler fail. I bodged it temporarily with tie-wraps and jubilee clips until I could get a replacement and the seal wasn't 100%, so every time the revs rose beyond 1,800, the hissing started...

There was also less power [although not as drastic as when the pipe blew off alltogether!]

It stopped when I renewed the pipe. If you aren't sure, get someone to give the throttle a good prod [but don't over-rev!] while you listen under the bonnet and you should be able to audibly locate the leak if there is one, it will sound very different to the normal turbo sound.

Cheers

Guy

leemasiuk
18-04-2007, 04:19 PM
Thanks for the input guys,

I still haven't got to the bottom of the problem. I still think its some sort of air leak, like has been mentioned.

My car is in for a repair after rolling down a hill and into a post! Handbrake not fully on.

I will try listen under the bonnet for leaks once i get her back.

The issue does sound very similar to Lightweights description. If you find anything from the fault check, please let me know

thanks

Lee

sugs04
23-04-2007, 09:39 PM
Did you find out what it was?

Lightweight
24-04-2007, 07:30 PM
Mine went into garage, they found a loose intercooler pipe... one new clip later and its all better.
Cheers

leemasiuk
05-05-2007, 04:36 PM
Just an update to thank everyone and confirm the problem

As several of you suggested it was an air leak, and it was from a pipe connected to the intercooler.

Thanks

Lee

Stu_c
05-05-2007, 07:33 PM
that was the problem on mine the rubber sill went on mine

gavbarlow
10-05-2007, 04:34 PM
I've had the same problem. Sudden loss of power whilst driving, clouds of black smoke at 2000 rpm+. Turned out to be the bottom intercooler pipe. The retaining lugs had given up and the hose just blew off. Easily fixed with a new connector between the intercooler and the hose (basically a short piece of orange hose with ally ends) Cost £30 approx from the dealer. 10 mins to fit, and it was sorted. :biglaugh:

Stu_c
10-05-2007, 06:53 PM
mine was the rubber sill cost me £3.59 (i have just relized my mates keyboard has the $ sign but no pund sign :mad: )