If you go to the Harbor Freight site and look up their leak back tester you will find there is a .pdf of instructions you can view.----------

Instead of removing one of the spark plugs you have to remove the injectors or glow plugs (you are going to need to buy or make a compression tester adapter for one of those areas) and us that to connect the compressed air to the leak back tester.----------

If all you want to do is listen to where possible leak is all you need is the compression tester adapter and a fitting to attach the compressed air. A filter in the airline to keep out any water vapor would be a good idea.----------There also may be youtube videos on doing the leak back test with the leak back tester.For specific values of the test you should consult the actual Mercedes Manual.

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84 300D, 82 Volvo 244Gl Diesel