RE: wrist pin sound
At what RPM are you hearing it knock? I still have two knocks in my 97 4.3 one that comes in at about 2000 RPM with NO LOAD, UNDER LOAD I don't hear it. It has been doing it for 12,000 miles hasn't gotten worse. I was going to replace the engine but as long as it keeps running I will just drive it. It runs great except for the knocks. I also have a knocking noise at idle that who knows what it is, It doesn't seem to be connected to the other knock I only hear it at idle. It has not changed in 12,000 miles. So I have just decided it can knock all it wants as long as it keeps running. I had a 1973 IH 4x4 pickup with a 345 cubic inch V8 & it had a knock, so I completely rebuilt the engine All new bearings, crank, cam, etc, had the heads rebuilt completely, put it back together & 50 miles & the same knock was back. I drove it for 70,000 more miles sold it to a friend that drove it for at least 5 more years before he got rid of it & it could still be running. When the Blazer blows up I'll call a tow truck & have it towed off the road & decide what I'm going to do. This knock has been heard by 4 different mechanics & every one has said it was something different, all said it would go much longer & I would find out when it blew up that was like I said 12,000 miles ago & it is still running great & knocking. Being a retired mechanic myself it must not be anything too serious or it would of come apart by now.