6.5 in military hummers

[KenDavis]

I enjoyed the article on the 6.5 diesel engines being in the military hummers. But the article did not say anything about what they did to combat the overheating problems, especially being in Iraq with 110-130 degree heat. Maybe what they did could help us? Anybody know?

[DA BIG ONE]

Originally posted by KenDavis:
I enjoyed the article on the 6.5 diesel engines being in the military hummers. But the article did not say anything about what they did to combat the overheating problems, especially being in Iraq with 110-130 degree heat. Maybe what they did could help us? Anybody know? I know H1 has extra cooling internal for the t-case because of heat issues related to its drivetrain tunnel and poor flow of air.

Doubtful any additional heat load has been put on them that they could not get at NTC in Death Valley.

Perhaps, someone that worked in maint could shed some light on what if anything was done to increase cooling of motor, or if it was needed?

[CareyWeber]

I know they have a hydraulically controlled fan clutch (ran off the power steering pump) that has a temp sender to tell it when to engage. The fan clutch is the only thing that I know of. I think if you dig through the threads here there is some info that the H1 has heat issues too, but it may just be the injection pump issues. Do a search on Iraq or soldiers and you might find some more info.

Carey

[markrinker]

Massive radiator as I recall.

[Cowracer]

Also, Its not exactly like they are pulling an 18000 pound 5ver up the rockies either.

The cooling system is usually up to par until you start towing

Tim

[NH2112]

I spent a lot of time behind the wheel of humvees in Saudi Arabia, Iraq, White Sands Missile Range NM, and Twentynine Palms CA, and don't recall any real overheating issues. The armored models (M1025, etc) run hotter than the soft-skinned ones (M998, etc) because the radiator grille is armored and doesn't allow for as much airflow as those on the M998. However, I've never seen one even come close to the 230F red zone on the gauge, mainly because when that fan clutch kicks in it REALLY moves some air! I'd estimate it uses close to 10% of the engine's available power to turn that huge fan with deeply-scooped blades, and you can literally see the temp gauge dropping when the clutch does engage.

[Tractor]

A buddy I work with spent 2 years in Bahgdad, Irag. So I asked him today about the heat over there. The hottest he saw over in Bahgdad was 130 degress. The group he was in had several hummers, all with heavy metal armour. The gauge was never hotter then 220 but the fan almost always was running. They never had a bit of trouble with the hummer. They just had a hard time finding jacks tough enough to lift them up to change tires. They were so heavy and the sun was so hot jacks would just give out. To his knowledge there were no add ons. He said we never worried about them breaking down, just worried about bullets, bombs and missles. The suspension could have been a little stiffer to handle the extra weight of the metal.
TRACTOR

[TJ]

I have extensive experience in both operating and repairing 6.5L NA H1. Both sober, and well, not so sober. My experience includes very tough service and abuse on them. The fan clutch on the Hummer does work and come on a lot more than in a standard truck. And, the radiator appears to be larger. We've played with hood scoops on them to try and attract more air through the radiator. Those do not function well and are best left alone. In stock form, there are no overheating problems what so ever. However, few people actually tow with their Hummers.

TJ

[garre1tt]

My experience with the hummer has always been good. Been to the NTC (National Training Center, Ft Irwin, CA in the Mohave Desert) three times each at least 120 deg. What I have not seen mentioned is the amount of governing on the vehicle. On the highway if you can get it up to 65 down hill, you are lucky. When that hydraulic fan kicks in 45 max.
Michael D.