HMMWV Overheat Q's and pictures

[Retiredwarhorses]

My ‘02 M1035A2 cycles just under 240, engages the fan and drops to 224, then rises to back to just below the 240 line. I verified the fan clutch to be operational. The TDM was disconnected when I received the truck from GovPlanet. I performed all the fluid and filter changes. I have driven about 500 miles with this, tried another temp gauge, replaced the sending unit and fan switch with Hummer Parts Guy parts, replaced the thermostat (HPG part), replaced the Cadillac Valve and TDM (no effect on the cooling cycle), flushed the Radiator three times, and replaced the lower metal coolant tube with a stainless steel one. I added WaterWetter to the coolant. I have a Gano Filter in the upper radiator hose that traps particulate and can be removed and cleaned (3 Xs so far with sludge and small rust chunks removed from the system) and after all this the temp range while driving remains unchanged. Ive read that these trucks routinely operate in the 220 to 20 range but would like o see it cycle at 225. What say you guys?

should never get past 220 before the fan engages…the thermostatic switch is likely the culprit, but have you actually verified this to be truly the temperature? Have you changed the radiator cap? have you verified you have built pressure when at operating temperature?

 

[Mstng65HummrMan]

should never get past 220 before the fan engages…the thermostatic switch is likely the culprit, but have you actually verified this to be truly the temperature? Have you changed the radiator cap? have you verified you have built pressure when at operating temperature?

I have a new radiator cap, i used a laser thermometer on the upper radiator hose that showed 71 cold then up to 193 at temp. I got readings on many different pat like engine block, lower radiator hose, crossover, etc, and non was over 200. I did buy a used temp gauge, installed it, and it read the same…

I have not verified pressure though, although I have released the overflow cap pressure to burp the system at operating temp in an effort to alleviate air from the system. It seem to make a difference with fluid level but not temperature indicated.

 

[Retiredwarhorses]

I have a new radiator cap, i used a laser thermometer on the upper radiator hose that showed 71 cold then up to 193 at temp. I got readings on many different pat like engine block, lower radiator hose, crossover, etc, and non was over 200. I did buy a used temp gauge, installed it, and it read the same…

I have not verified pressure though, although I have released the overflow cap pressure to burp the system at operating temp in an effort to alleviate air from the system. It seem to make a difference with fluid level but not temperature indicated.

if the upper radiator hose is hard, it’s pressurized.
i would run a wire direct from the engine temp sensor to the gauge…I’ve seen high resistance shorts cause erroneous readings.
just run it out side of the truck and plug into the gauge, just for a test.

 

[911joeblow]

These temp gauges are notoriously inaccurate and usually on the high side. That being said you are still going to run hot at the back of the block compared to the front which is well documented and a cause of most blown head gaskets, cracked heads/block, scored cylinders etc.. (almost always in the overheated #7 and #8 cylinders). Look at our cooling balance kits to solve this issue, with a side benefit of constant bleeding as well. https://paradoxbydesign.com/collect...oducts/hmmwv-humvee-cooling-upgrade-system-v3

 

[TOBASH]

Rear cooling kits are at the best controversial.

 

[Retiredwarhorses]

Rear cooling kits are at the best controversial.

garbage.…save you’re money. I have a great right up with pics on why it’s actually not good to install a kit because It can actually cause
hot spots.

 

[911joeblow]

Our kits are installed around the world, in every climate you can imagine in military use, off road race use, exploration use and of course enthusiast use. They have and continue to perform just as engineered and well tested to do. There is no refuting the benefit of these kits other than loose conjecture and from the hip sidebar comments. These are WELL tested and proven with thousands upon thousands of hours of real word use.

 

[TOBASH]

Our kits are installed around the world, in every climate you can imagine in military use, off road race use, exploration use and of course enthusiast use. They have and continue to perform just as engineered and well tested to do. There is no refuting the benefit of these kits other than loose conjecture and from the hip sidebar comments. These are WELL tested and proven with thousands upon thousands of hours of real word use.

Respectfully, this has been discussed on many forums and the literature does NOT support these devices.

You are a good guy and I don’t want to generate ill will.

My last word on the subject.

 

[911joeblow]

Sorry but again actual testing has proven these kits to be exactly as advertised. These kits eliminate the endless list of band-aid products like oversize water pumps, duel thermostats, lower temp thermostats, aftermarket radiators etc.. Those that sell all that stuff are the only ones refuting our kits effectiveness, correlation?

 

[TOBASH]

garbage.…save you’re money. I have a great right up with pics on why it’s actually not good to install a kit because It can actually cause
hot spots.

Hey RWH, I hope by quoting me you weren’t implying that I support or endorse or agree with the use of these products.

 

[Retiredwarhorses]

Hey RWH, I hope by quoting me you weren’t implying that I support or endorse or agree with the use of these products.

no sir…the mfg is just trying to peddle his product, I get it, problem is…they just copied something out there that has been dispelled loooong before they ever manufactured their own product.

 

[Retiredwarhorses]

Quoted

In conclusion: Taking coolant out at the back of the heads reduces the amount of
coolant flowing forward and through the heads - plain and simple. That cannot be
argued. The cylinder heads generate most of the heat in a running engine, and the
cooling system has to move enough coolant through them to prevent damage. If a
bypass cooling strategy is used, you may see a lower engine coolant temperature, which
is what you'd expect if the coolant isn't picking up as much heat as it should in the
cylinder heads. Not removing heat from the cylinder heads could result in hot spots that
develop in the area around the exhaust valves and exhaust runners, which won’t be
reflected by the engine temperature sensor. I’m open to third party data and test results,
but till then my opinion is that bypass cooling may actually contribute to cylinder head
cracking - engine damage..

 

[911joeblow]

We copied absolutely nothing. We come from an extensive professional motorsports background and have a lot of mechanical engineering expertise for decades working for some of the biggest names out there. Just because you don't understand something does not make it and less effective. Your mechanic background just does not give you the engineering knowledge necessary in this case apperantly

.

no sir…the mfg is just trying to peddle his product, I get it, problem is…they just copied something out there that has been dispelled loooong before they ever manufactured their own product.

 

[911joeblow]

Everything in your statement below can be argued. We have NEVER claimed that our system is designed to lower overall system temperatures. We are creating a flow path that is inadequate in the stock engine design. Pretending this issue does not exist does not change the fact that is is both well documented and even in the factory service manuals directly. If you don't believe our data, fine, then believe the factory data. To date we have never had a single reported head gasket failure or cracked head after installation of our system. We have over a thousand kits in circulation. Good day.

Quoted

In conclusion: Taking coolant out at the back of the heads reduces the amount of
coolant flowing forward and through the heads - plain and simple. That cannot be
argued. The cylinder heads generate most of the heat in a running engine, and the
cooling system has to move enough coolant through them to prevent damage. If a
bypass cooling strategy is used, you may see a lower engine coolant temperature, which
is what you'd expect if the coolant isn't picking up as much heat as it should in the
cylinder heads. Not removing heat from the cylinder heads could result in hot spots that
develop in the area around the exhaust valves and exhaust runners, which won’t be
reflected by the engine temperature sensor. I’m open to third party data and test results,
but till then my opinion is that bypass cooling may actually contribute to cylinder head
cracking - engine damage..