New exhaust manifold - engine overheating

[NickP]

Just paid a small fortune to replace a cracked exhaust manifold. Took it on a long journey the day after and an hour in the wife who was driving noticed the temp light flashing and the gage was maxed out.

As we pulled off the road steam started coming out of the engine. So we switched off and managed to free wheel to a petrol station. After letting it cool I opened up the radiator which was pretty much empty and it looked like just a simple radiator leak. Anyway we topped it up to full and when I poured the water in it basically boiled up like mad so it mustve been super hot. We stocked up with water and set off again and it started overheating again almost immediately.

I figured something more serious was wrong some ditched the car and phoned the garage who did the work. They said it was highly unlikely to be anything to do with the work they have done, which obviously don't believe as it seems to much of a coincidence. He got me to start the engine up again and check to see if hot air car out of the internal heater which it didn't, after letting it run again for a couple of minutes stationary it maxed out again so we turned off and he arranged for it to be picked up. He said it sounded like the head gasket might've gone and it was probably unrelated. I'm going to speak to them tomorrow once they've diagnosed the problem but if anyone could give me any advice on what they think might be the problem that would be good. It seems glaringly obvious that this has been caused by something they have done but I get the feeling they're going to deny tis and I'd lke to be armed with the facts. Anyone got any thoughts?

[NickP]

Quick update to this. The garage have not looked at it properly yet but said water pump is a possibility because it doesn't appear to be circulating.

Any thoughts are really appreciated.