Hiss while accelerating? 02 mkiv Golf TDI PD 100hp (ATD)

[maskedwarrior]

I hear a hissing noise when I accelerate at low revs in 3rd, 4th or 5th gear. Most noticeable while passing houses, walls etc with the windows open. I can hear what I call 'normal' turbo whine when I rev at stationary, but the hiss only happens when driving.

I found an oil leak at the egr valve and have replaced the hose clip there with a jubilee clip. Cleaned up the area. I left it a day or so and checked it, but can't tell if it's cured atm as I realized the foam that goes under the engine cover is oil logged, so have removed that and will check again in a few days.

The hiss sound has remained.

So in the mean time - could anyone shed any light on this issue for me? It's my first Golf so I don't really know what's normal noise and what isn't. I only bought it recently and it's made the hiss most of the time, although it may have got a bit worse... or perhaps I'm hearing it more because I know it's there!

Is the hiss described likely to be a leak of some kind? Or something else? Or normal engine noise?

Thanks very much,
Tony

[scarr89]

I think in general diesel engines are probably a little more hissy than petrols, especially older ones.

You could well have a small boost leak in your intercooler pipe work. Check the pipes, the seals can wear and the metal clips can sometimes break and cause the whole pipe to almost pop off.