Did this this afternoon. removed the no 28 fuse, connected pipes to the intake and return of the fuel filter and put them in a metal cocktail shaker. ( i wanted to see the level at all times of the Liqui moli diesel purge) as i wasnt quite sure how much it would use per minute for example.
Really easy to do, well worth it. engine feels much smoother now. and im sure i could hear the engine sound change ever so slightly.
the only thing that was a pain in the *** was the return pipe (8mm one) out of the filter. its a plastic connector and required much persuasion to get the original pipe off so i could attach the newer shorter one to the cocktail shaker containing the diesel purge.
please be aware that the container and the pipes will get hot when you do this. i suggest also doing this when the engine is cold, so that you dont burn yourself on the engine or the fuel when a little spills out when you disconnect the pipe.
i got myself the 1 litre version of Liqui Moli Diesel Purge, but 500ml would have also been sufficient. since my car has just over 124,000 miles on it, and not being sure on whether the injectors are original or even if they have been cleaned in the past, i thought id go with the 1litre the first time. i would probably just do 500ml from now on, possibly before a service.
i was really quite hesitant about doing this at first, and not to mention the possibility of getting air into the fuel system, but its really easy,
and i came across no problems. just make sure that you put plenty of kitchen roll around the fuel filter so you dont get diesel all over your engine bay when you disconnect/reconnect the fuel lines to the filter.
