GM-GMC: gmc diesel, gmc diesel, flow water

Question
Hi i own a range rover with a 6.5 turbo diesel gmc engine thats just cracked the block,its casting number is 506 ,1997 i think,can you tell me if the 6.5 non turbo suffers from the same problems.The engine im looking at is 95 model i think but its expensive,or would i be better off fixing my own engine and upgrading the cooling system.Thanks in advance for any help you can give.

Answer
Tony,

I had a 506 go bad on me, too.

The 6.5s from 1997 to early 2000 have the problem.  It resulted from GM cutting back on the amount of cast iron at the #8 cylinder.

Earlier 6.5s, and the newer ones being made for AMG (Hummer) production are okay.

The best block is 10149599.  It was available in 6.2 or 6.5 in the 1992-1993 production years.  I have a 6.2 version of that block and it has no problems.

Your engine should have the dual thermostats and high flow water pump, as those changes came out in 1997.