UK Car Repair: Clearing out sludge, vauxhall astra, oil pipes

Question
QUESTION: Do I have to retorque the head bolts on a Vauxhall astra 1600 8v club after 500 miles run in of a new head gasket? If so, what are the torque settings/ tightening angle? The Haynes Manual only specifies the intial 4 stage tighening sequence.

ANSWER: You do not have to re-torque it.

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QUESTION: Hi there,
Thanks for your answer.
I also need to know how to rid my engine from the yellow sludge that is in my rocker cover and oil pipes. I've been advised to flush the engine using flushing oil. Would this be sufficient or is there a better way? Since changing the gasket, I've noticed some oil consumption. I think that this is due to to the already present sludge mixing with the new oil but would like to know for certain. I'm not loosing any coolant.

Answer
It is difficult to flush out and often can cause more problems BUT, we sometimes mix paraffin or kerosene with very thin oil, disconnect the ignition, remove the spark plugs and turn the engine over enough to circulate it well.  You then need to flush it out twice, to remove the mess.   I would suggest running the engine until it is hot then drain and refill.  You can do this, say monthly, until it clears out the mess.