Do you disconnect hoses to change AC and alternator

What is your question?

I own a 2006 650i BMW. The car has been the best running and looking car I ever owned .I take excellent.care of it always checking the fluids. The AC compressor blew and I gave it to my mechanic to fix. I picked it up and on the way home it died and he said it was the alternator. So he fixed that and I drove it maybe 5 miles and it just died again. No steam and no hot lights came on. I tried to start it and it was turning over but sounded like it was dragging. My mechanic picked it up and said it was a blown engine because of no water. I ask him if he filled it up after he did the job and he said what dies that have to do with me. I looked inside the engine 100's of times and you can hardly get your hand in. I was wondering if anybody knows if you have to take off hoses if you did those jobs and I also heard that there is a heat sensor in one of the hoses that he may have forgotten to put back on. Jerry

What makes this problem better or worse?

Can't get worse

How long has your 2006 BMW 650i had this problem?

5 days