Mercedes OM602, 2.9, 5 cylinder Diesel Injector and injector pump clean on a 1993 s660 Hymer Motorhome using Liqui Moly Diesel Purge.
The upshot was I was getting a knocking/chattering noise coming from the injector area of the engine and after some research I decided to have a go at using a product called Liqui Moly Diesel Purge which has some superb reviews for It's ability to clean the fuel injectors and the Injection pump which may over time have become gunged up causing poor performace to an older engine like mine.
Basically I bypassed the main fuel tank by disconnecting the fuel lines from the main fuel filter and then connected one end of the 8mm clear vinyl tubing into the inline fuel filter (used a new one) and the other onto the return line on the main fuel filter.
The Liqui Moly becomes your fuel and cleaner during the process which lasts about 10 minutes per 500ml container. The instructions advise you to rev your engine at various points to maximise the effect of using the cleaner.
You can repeat the cycle again using as many cans as you wish (I used 2 x 500ml containers)
You can see from the video the difference in sound from the engine before and after the clean is remarkable and you can also see the debris collected in the small inline fuel filter as a result of the purge. During the initial purge process I observed the colour of the purge fluid was almost black showing it was doing It's job.
Prior to reconnecting the fuel lines I replaced the main fuel filter and the small inline filter with new ones.
So the results, once back in normal operation the knocking/chattering was significantly reduced almost to the point of being gone completely and having done this video a few years ago I can say I was surprised looking back how noisy the engine was in comparison to how it sounds today with no other intervention. Old Diesel engines such as the OM 602 are almost agricultural in design and will never sound like a modern diesel engine but taking a few steps to clean systems out will certainly help as shown here.
Please note Diesel purge is not going to help with an engine that has mechanical issues, it is purely a cleaning product designed to remove crud build up from your injection system. Please follow the manufacturers instructions when carrying out your Diesel clean if you decide to go down this route.
I hope this helps someone.
Thanks, Jon