Had the injectors done on my TD4. Fitted the cover again. Drove home and the vehicle only boost from 2,5 - 3. Got the cover taken off and then the hole on the left side where the cover gets screwed on, spitting out oil. First time this happend. We drove without the cover for a couple of days, waiting for the new injector to arrive. Got it fitted today, and cover re fitted. What could this be?