[ssgharkness020147]

I bought my 98 with 71K on the it and have only had to replace the FSD, which is a the computer module on the injector pump (a VERY common problem). I am about to roll over the 81K mark in the next week or two and the only other thing that I have noticed is that the truck burns 1.5-2 qts of oil between changes. That is out of spec but I dont mind having to top it off every now and then. The 6.5 is an all around good engine, but it leaves alot to be desired in the performance catagory. The main issue is the blocks cracking this was not fully cured until 01, on the plus side most used trucks have the updated engines already. The way to make sure that you do not have this problem is to update the cooling system. The high flow water pump from Kennedy diesel along with the external cooling kit for the two rear cylinders will cure the cooling problem. If a 6.5 is properly cared for it should go at up to 250K. I would give a HUMMER engine a lifespan of 200K if the engine is well cared for. Someone on Humvee.net got 150K out of theirs others have over 120K and have reported no problems. I have seen some that have gone to over 600K, but not in a HUMMER. The 6.5 has to work alot harder to move a HUMMER around then it does to power a pickup. In my opinon to get the max life out of a HUMMER engine you have to run it in the RPM spec (reccomended operating range is 2450), maintain the engine and truck on the "severe maintinence" shedule, and add the cooling kit.