Opinions on GM 6.5

orange150

orange150

Well-Known Member
Joined
Mar 20, 2005
Location
Fairfax City, VA
I know the general sentiment of them being a dog etc., but are they really that bad to live with? Been keeping my eye on GMT400 2500 burbs, would prefer the 454 but I've seen a few clean 6.5s pop up somewhat close to me that I'm curious if I should really pass them up if they're clean enough.

The only thing I really know about them is the PDM needs to be relocated if not already done.
 
skyhighZJ said:
FWIW we ran the dogpiss out of a turbo 6.5 in the HMMWV. Motor wise they were pretty stout. @Tacoma747 may have some insight?
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Well, the old non turbo 6.5 is essentially the same as a GM 6.5 of the same era I think, but the turbo variants are more similar to a VAN style 6.5, which is a completely different set of heads, intake, and turbo.

The biggest difference would likely be that all HMMWV engines are fully mechanical whereas the GM trucks and vans has a computer controlled injection system which could have issues I think. That said, I think 'fatal' issues are not a problem, just common stuff like the engine computer, maybe cracked heads or blown head gaskets??

After 2001, all HMMWVS had GEP engines, which was basically a knockoff of the GM block/heads, but with stronger/better casting materials used.
 
And on a further note, back around. 2011 I had a job where the company used surplus government express vans with the 6.5. We had an in-house mechanic that worked on them so he knew all the common issues with them, but for can use, they had plenty of power. If you want to tow a 8,000 lbs trailer up black mountain, you are probably going to be wishing for more.
 
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