mk4 gt tdi 130 turbo hissing noise - wastegate?

[leemasiuk]

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.

Thanks

Lee

[mkpp786]

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]

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]

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]

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]

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]

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]

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]

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]

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

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