I recently purchased a '92 300D with the 2.5 turbo. Great car! On pre-purchase inspection the seller had a shop check compression and fuel injection pump pressure, removing the number one fuel injector. It has been leaking between the injector body and injector where the two screw together. I've removed, re-tightened, no luck. Is this a sign the injector has gone bad?

Also, now that I can see the whole area, I notice small bubbles between the prechamber and the head where a small amount of fuel has accumulated, suggesting that the seal between the two is not up to snuff. The engine has 140K on it--can this be remedied by buying a splined socket to tighten the prechamber nut? Or, is this a sign of something more? Anybody haev any experience with these demons?