Checking for cracks in lower block

[jerry598]

I described my head problems in a separate thread, but I still have a concern or two about my 929 block. It's a 95 6.5 turbo K3500 (125k miles) and I pulled the heads due to a burping coolant problem (probably caused by cracked head gasket on RH side of #7 cylinder - the only place on the heads where I found any evidence of darkening or discoloration and there was evidence of a crack in the gasket at that location). The block is still in the truck. The topside of the block looks good to my untrained eye, no erosion or pitting, no evidence of cracked pistons or cylinders. My question: Is it worth it to drop the pan and check for main web cracks or other problems from the underside of the truck? Is it even possible? Or will the crank and bearings just all be in the way? I know I would not be able to detect all cracks just by dropping the pan, but would it be a good idea to do so before slapping on new heads and planning a fishing trip to Alaska? Would it be possible to detect any cracks at all by dropping the pan? If so, should I blow torch the surfaces and look for oil seeping from cracks? Or would all of that just be a waste of time?

[Locomoko]

Not being an expert but... I had a cracked block, took quite a bit of effort to discover where the crack actually was (#1 cyl wall, traveled up from the inner main web. After looking at a few pictures on this forum of cracks in the main web area, it was easy to see where mine originated from. I also rejected a take out block after a machinist sent me photo's of the same inner main webs (it had a crack). All this being said and considering you are planning a long trip where fixing the rig on the road would be expensif, I would say take the pan off (ugh) and the inner three main caps, clean the area with diesel fuel or some other suitable cleaner, wipe it and with a good bright light inspect the area in question. If you see nothing that reminds you of other cracks you have seen then proceed with the heads/gasket. After it is all put back together start/warm up the engine then shut down, put a pressure tester on the coolant reservior & pressurize to 12 or so lbs. (more doesn't translate to better) Then wait to see if the pressure drops overnight. Take it from there.

Please note this is what I had to do to find my leak, and you are getting the condensed version. Hope this helps. Aloha, & now for some fishing tales. :)