How is oil getting to my wife's Renault Scenic's spark plugs?

My wife's Renault Scenic (nine years old and 69,000 miles) has just had a new cam belt fitted. When I picked it up it seemed to be misfiring badly. The garage fitted new plugs - no change. They suggested it was a coil. When I went to pick it up today they said there was a problem, in that oil was discharging over three plugs. There was no oil from the car standing still. They have not seen the like and will investigate the manifold breather. I would welcome any suggestions as the garage are at a loss to the cause.

Asked on 25 July 2010 by domfascia

Answered by Alan Ross
Possibly failed valve stem oil seals.
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