1997 Polo 1.6 petrol saloon - 69000 mls.

Hi, could anyone give advice /opinion on the following.

I had a small drip of coolant from my water pump at the end of Feb 2008 (noticed this on garage floor and small drop inlevel of coolant). Coolant level never fell below minimum, as I topped it up, and temperature was always normal. I have had the car from new and therefore know that there has never been any previous cooling problem.

My local VW specialist changed the water pump and found no other problem with the cooling system and I used the car around my local town for 3 weeks (250mls approx) with no problem. No leaks or coolant level drop.

On Good Friday I set off on its first long, motorway speed, journey since the water pump was changed (all levels checked before setting off and no leaks on garage floor) and 45 miles into this, in the outside lane of the motorway, the heater sudenly went cold and the temperature gauge shot to full scale. As I was trying to get between lorries in the near side lane to the hard shoulder I started to lose power. Fortunately I survived and reached the hard shoulder and found no coolant (not a drop) in the system. Called RAC who tried to put water into the system but it came straight out from the water pump area. RAC found that the plastic connection elbow that connects the bottom hose to the water pump (it looks to be a push on connector with a locking circlip) was disconnected (circlip still in place) and water poured out of here. His opinion was that it had not been securely replaced when water pump changed. He also felt the loss of power was probably a blown head gasket due to the over heat. He recovered car on a trailer to VW specialist.

VW specialist, who changed the water pump, inspected car and his opinion was that the head gasket suddenly blew, pressurizing system which then disconnected the pipe connector elbow at the water pump, i.e. nothing to do with anywork they carried. When replacing the pump they did not renew the plastic connector.

Has anyone any experience of this type of connector separating under pressure from blown gasket or, alternatively, separating due to incorrect fitting(after it had sealed for some 250mls)?

Thanks
Nigel