"3) While I agree with mr LooKnee that HG failure is rare on the V6, I have seen it happen twice (on badly maintained cars) and strangely it's always been the passenger side one that's gone."
My head gasket went on my 2001 2.6. The car has a full MD service history and the gasket went at around 56k. A cloud of white smoke at start up, white smoke under heavy acceleration and exhaust in the coolant. Once removed, both off to be sure, I looked at the gasket and head and you could see a slight scorch and a ‘channel’ where the water was escaping. It was very minor but was causing the coolant to burn off and all the other problems associated.
It maybe rare but this can happen to any car, regardless of maintenance. It is a perishable item after all so please do not be blinkered just because it is rare for it to happen or it only happens to thrashed poorly maintained cars, it doesn’t.
Just because a car has service history, doesn't mean the service quality was any good......
In the case of a head gasket failure its generaly due to in-correct anti freeze mix and you can bet your life it was not changed as part of any service.
Plus, if its loosing some coolant then its not un-common for it to be topped up just using water and no an anti-freeze mix which results in a week antifreeze mix.......