Noisy first 5 minutes

[marbul]

Hello

I have a MB 208D van from 1991. In the first 5 minutes of running there's always a ticking/clattering noise. I've tried using Liqimoly to flush the injectors but doesn't seem to have done anything. Could it be an air leak as I've read that it might make a noise like that? If it is an air leak would it be there all the time or would it come and go. Am in Bulgaria at the minute and its really, really hard to get any kind of info and very easy to get ripped off. Any help appreciated.

Thanks

 

[marbul]

Have just read my last post and seems pretty vauge
I have a problem with noise in the first few minutes of stariting up the engine if the accelerator is not depressed the engine sounds normal but when depressed there is a fairly loud ticking /clattering which gets louder as the revs increse but after a few minutes the noise goes
It does return at some points ie after rolling down a large hill without depressing the accelerator ,it returns for a few seconds when the accelerator is depressed again.
Sounds like it is coming from the top half of the engine have been used to doing basic repairs on all my veichles but this is the first time i have owned a Mercedes or a diesel.
Have recently changed the oil and filter ,fuel filter and have flushed the injectors with a good dose of liquimoly to no avail.
Any ideas would be greatly appreciated