Ticking sound D5 injector
 

Like many others I've got a ticking sound coming from one or more injectors when accelerating. The sound suddenly stops at 3000rpm. There is no sound when you keep the same speed or when you're very gentle with the throttle.
I've listened to the injectors with a long screwdriver and nr. 4 and 5 are making more noise. I've got no problems starting the car and a injector return test does look quite normal.

http://i65.tinypic.com/rr8r40.jpg

When I disconnect injector nr. 4 the car keeps running, when I disconnect nr. 5 the car stops.

Is there a way to tell which injector is fault?

It's a 2002 S60 D5, 570.000 kilometers

Did you get the bottom of this?

No I dind't. I bought two cans of Liqui-Moly diesel purge and added it to the diesel. That made a huge different, but after a certain time the noise returns.
I thinks it's a problem with the computer/injector, because when I disconnect the battery, the first trip afterwards is without any noise. I think there has been a injection time reset?

My car has more than 650.000km at the moment so I don't think it's a real problem....

If you know the solution, please let me know!

Add 350ml of low ash mineral 2 stroke oil to a full tank of diesel and it will quieten down the injectors substantially.

I've done that for a long time, but it's not a repair, just a symptom control. I mean, why isn't there any noise after a battery reset?

And it will work for how long if i may ask? Is it safe?

You're complaining about a symptom so if the symptom disappears, why not continue?
Perhaps your injectors are just worn, perhaps they've been changed in the past but not had the ECM updated.
There could be several things.

In my experience, it works instantly and lasts for several tankfuls of fuel.
It's never done any harm to any diesel I've used it on.

I've started to run on biodiesel and this has quietened down the noisy injectors quite a bit, my previous D5 had the same issue and over time running on biodiesel the noise slowly vanished.

I've read that the noise is actually pre-ignition caused by a poor spray pattern, the nozzles of the injectors gum up and cause issues. Biodiesel slowly strips the deposits in the diesel system and cleans the injectors. Just a theory of mine! I'll continue running on biodiesel and report back the results.