[96 gmc 1500]

Hi, I have a 96 Gmc 1500 p/u with 125K miles. My truck has been running just fine, but I have not had a tune up in a while and was told I need a new fuel filter and plugs, so I just had it in the shop for new plugs, wires, fuel filter, oil change and filter, power steering line fixed that was leaking and differential was leaking and fixed. They also said they checked everything else, fluids, belts, brakes, etc.
Driving home from Denver to Durango, around 200 miles in, I heard a ticking from the engine when climbing a hill, then went away. There was also a slight smell of what I thought was antifreeze the whole way. About another 60 miles the ticking started again and became louder and when I finally pulled over, it was a loud knocking that stays on in idle, but so far, the truck still drives. I had it towed the rest of the way to my house, but any ideas? There was oil, I checked when I got home. Oil pressure and engine temp gauges were normal. The tow truck driver listened to it and said the engine is blown?
Jenni

[CaptainRich]

Some light ticking is not uncommon, but knocking? That could be anything from a rod or main bearing to a possible piston wrist pin. I would recommend having this checked out before it goes larger.
I wouldn't necessarily say that it's blown, just yet.