If you insist on removing what looks like an Aluminum Crush Washer get a propane or one of those small butane torches and heat it up and carefully use a pointed knife or a pointed thing like an ice pic to see if you can get under it and pry it off while it is still hot.
Replace it with a Copper Crush Washer. Harbor Freight sells an assortment and I also believe that places like AutoZone have them.

You can make your own aluminum crush washers from something like an aluminum nut can top but you can't just drill a hole through it without it getting ragged. You have to press it between 3 sheets of wood when you drill the hole. That way the hole comes out fairly clean. The nut can aluminum lid is thin enough you can cut the out side of it with a big scissors of for sure a sharp tin snips. The out side does not need to be round just so there is enough metal in the sealing area.

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84 300D, 82 Volvo 244Gl Diesel