I recently found my rad cracked along the top as so many do, so I got a replacement, swapped it in. Drove it. Noticed another coolant leak. The o-ring was bad on the drain cock so had to fix that. Drain and refill again!

Then... and I cannot make this stuff up... my heater hoses both blew. Drain, replaced, refill. Then the heater core went. I noticed fog on the window and the sweet smell of coolant again.. the kicker? I had just replaced the heater core a year to the day before. Finally, I say to myself, there is literally nothing left but the water pump to go now. Want to guess what happened?

Yes, the water pump then failed. The bearing went and the pump was grinding away the housing. So I have now got an entirely new cooling system.

I have never heard of anything like it, and, as a mechanic, I am at a loss to explain why this happened, but I had to share since it had just been so ridiculous. I swear if I smell coolant again I'm tossing the car off a bridge. (Just kidding...maybe..)

Green? You should be using red, that's clearly why everything fell apart.
They're either old parts or crappy parts or it is possible your coolant was really that bad/acidic and caused problems.