So tomorrow i will pull the blazer in shop and get back on it. I paid $400 for it. Its pretty clean inside and out. Only 139000 miles on it. I can tell that there was some kind of coolant leakage at front of engine. I see a new water pmp on it. The temp send unit if thats what its called is melted out of the socket in the engine block. The PO said they had somebody look at it and said it had a valve problem. Ive taken the driver side valve cover off, valves look fine, and did see like tannish color residue in 2 spots in top of valve cover. It simply sounded like it had a miss in the idle when cranked. Did not drive it for fear of more damage. Horrible rattle in the cat. Suspect it is coming apart inside. Hope I didnt post this in wrong section. Will try to post update in engine/tranny section tomorrow. Thanks to all.