I have a 2000 K2500 (old body style) 7.4L a/t, a/c, long bed extended cab 4x4

Engine has a ticking noise mostly when cold. I think it is the lifters or maybe the rocker arms. Is there a way to test the lifters? This has 173k miles, so I dont know if I want to put alot of $ in it. Also, I have noticed an antifreeze odor, but have not found a leak. I had the intakes and valve cover gaskets replaced a few years ago. The GM tech who did the work though, really screwed up everything else I had him do. He installed the carrier bearing on backwards and didn't press it on. He beat it on with a hammer. Anyway I would not be surprised if there was a problem there. Any help would be appreciated. Thanks.