If your engine has the Prechamber Retaining Rings with slots and the Injector screws into the Retaining Ring it talks a 27mm Socket. Because, the thread in the Retaining Ring and the Injector are 24mmX2.0.

If you have Splined Prechamber Retaining Rings the Injectors thread into the top of the Prechamber (22mmX1.5 threads). I believe that is the one you need the 22mm Socket on.

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84 300D, 82 Volvo 244Gl Diesel