Hi All, Just bought my first diesel,6.5L Optimizer 6500 engine in 1995 Sierra 4x4. Engine out of 2007 military Humvee, and 4L80E HD tranny out of another military Humvee . All preliminary research before purchase says that if I care for maintenance this truck will out live me ... Any thoughts out there ?
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Newbie to 6.5
- Thread starter CaptSam
- Start date
BIGR
Lucky To Be Here
Welcome CaptSam, the 6.5 experts will chime in shortly.
MrMarty51
Well-Known Member
Welcome to the forum CaptSam.
Will L.
Well-Known Member
Welcome!
Somethings to know- the optimizer you got is the best casting of the 6.5 engine except one rare version which is not available any longer called p400. So good find.
However- the military burns through these engines like candy to a 8 year old boy. Overheating is #1 problem and the military is convinced 230, even 240°f is ok.
HORRIBLY WRONG!!!
200 ok, 210 watch the temp gauge more than the road, 220 pull over and let it idle back to 195 or below.
Many people say it’s really a coin flip if military take outs are good for the normal 200,000-300,000 miles. Never seen it happen if that engine had 5,000 miles on it from military.
If you have to drive it- do so but pay attention. Unfortunately they just get pushed hard and get hot taking the temper out of the rings and scorching bearings- especially if it was a hmmwv engine instead of a cucv.
Best is if you pull it out, put new rings and bearings, clean the flashings, and balance the lower rotating assembly. All that will set you back almost a grand If you diy except the machine shop balancing- but then with a few parts swapped at the normal 100,000 mile mark (balancer and injectors) you are set for 300,000.
Btw, yes I am the chicken little guy here. I point out worst case scenario, then walk doen from there. Firm believer in hope for best, plan for worst.
Also depending which thermostat crossover and fan clutch you have- (pics are a really good thing) you might just swap those and run it or maybe add a secondary temp gauge installed in the right rear head and see how she does.
The 6.5 is a good engine IF YOU CORRECT the known week points. Otherwise you can do a little reading online and find out why so many hate this engine. Don’t correct the short comings and she is a money pit.
Somethings to know- the optimizer you got is the best casting of the 6.5 engine except one rare version which is not available any longer called p400. So good find.
However- the military burns through these engines like candy to a 8 year old boy. Overheating is #1 problem and the military is convinced 230, even 240°f is ok.
HORRIBLY WRONG!!!
200 ok, 210 watch the temp gauge more than the road, 220 pull over and let it idle back to 195 or below.
Many people say it’s really a coin flip if military take outs are good for the normal 200,000-300,000 miles. Never seen it happen if that engine had 5,000 miles on it from military.
If you have to drive it- do so but pay attention. Unfortunately they just get pushed hard and get hot taking the temper out of the rings and scorching bearings- especially if it was a hmmwv engine instead of a cucv.
Best is if you pull it out, put new rings and bearings, clean the flashings, and balance the lower rotating assembly. All that will set you back almost a grand If you diy except the machine shop balancing- but then with a few parts swapped at the normal 100,000 mile mark (balancer and injectors) you are set for 300,000.
Btw, yes I am the chicken little guy here. I point out worst case scenario, then walk doen from there. Firm believer in hope for best, plan for worst.
Also depending which thermostat crossover and fan clutch you have- (pics are a really good thing) you might just swap those and run it or maybe add a secondary temp gauge installed in the right rear head and see how she does.
The 6.5 is a good engine IF YOU CORRECT the known week points. Otherwise you can do a little reading online and find out why so many hate this engine. Don’t correct the short comings and she is a money pit.
Welcome @ CaptSam ...don't let will scare you off from these engines..lol... (Although he is right about the shortcomings of it.). We got probably the best experts for 6.5td engines on this forum...you'll learn more here than anywhere else I've found....just do your self a favor get on her and ask before you change anything on your engine... Let these guys guide you and advise you on things... otherwise you'll make the same mistakes we have....
dbrannon79
I'm getting there!
