Noisy tappets in start up. ???flush

Lady owner, and it's my 1st RR2.5 diesel. (2002 p38)
Problem is noisy tappets on start up, but clears a little bit after 3-4 mls, or when hot.
Seen advise on this site, and need to know what engine flush (make) to use. Every motorists shop keeps recommending all products, up to a complete tappet change, which i dont want to spend that amount of money, without first trying flushing.
Any advise, would be much appreciated.

My advice is dont use flush, its the spawn of Satan

Get a cheapy oil, do an oil change, run the engine up to temp and then drop the oil again and fill with your usual decent oil.

Flush contains strong detergents and some will stay in the engine and this will break down the fresh oil you put in which isnt good.

I know there will be people who will say they use it all the time and never had a problem but as a lube systems technician i cant recommend its use

Wynns have a product which does actually work. Wynns Hydraulic Tappet additive, which is actually used as part of the Subaru Impreza's routine servicing, due to the problems with that engine.

It's not a flush, like an engine cleaner. It just sits in with your usual engine oil 'till the next oil change.

I've used it on a couple of different LR V8's and it generally works.

What grade of oil are you using in the M51 engine in your P38?