Two points here.
There was a particular series of these coils which had problems in the manufacture. You are correct, whilst most non Renault cars have just one coil with five thick cables running to the plugs - Renault immerses separate cigar shaped coils virtually into the engine block. It is amazing that they work so well situated where they are - Being literally fried!
Whether your coils were part of this batch, the Renault garage should be able to tell from the vehcile registration.
Secondly they do seem to fail like a dominoes -
hence some garages replace the lot at one go, whilst
other places (to save cash!) replace the faulty one only. Then, invariably the others fall too. Usually at a very unfortunate time.
Symptoms:- Engine performance becomes erratic.
Genuine Renault parts cost around  45 each, then the fitting - simple but a charge +VAT. Hence a bill for four is eye watering.
Probe Distributors - on Internet (I've no connection - used then though previously.) Deliver in 24 hours
at a massive saving. They used to give a three year warranty too.
Warning - Whilst to replace these coils is simple, watch the line up. The small securing screws must be handled carefully. Easy to break these off, although the coil collapse should still hold onto the plug tops.
Not sure whether the EMU then rests itself thereafter.
Sadly Renault symbol warnings on the display, have a habit of requiring a special piece of kit to clear off these dashboard notices.
Just bought another Megane though - Must be mad or can cope with the odd heart stoppings.
SamWoe
Thursday, November 19th, 2009 AT 1:18 AM