Humvee cooling issue

twisted60

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Need help figuring this out, my 2006 M1152ECV 6.5 Turbo gets hot when I drive, sitting in drive way I can let her run for hours no issue. So what I've done so far;
Changed all hoses, new surp belt, new OEM thermostat, flushed radiator, fresh antifreeze mixed to 50/50, preformed eng block test (passed), tested thermostatic fan switch, tested time delay, tested cadillac valve. Fan kicks on at ~205 and off at ~195 (sitting in driveway) driving fan kicks on but temp doesn't come down goes over ~235 and the "hot" light comes on, lifted oil cooler and checked for blockage between cooler and radiator, blew air thru cooler and radiator fins, combed cooler fins, transmission oil level just a tiny bit above hash mark, power steering oil level middle of sight gauge (cold), engine oil level full. -10 says normal coolant temp 195-250 .... My M998, fan kicks on at ~205 and off at ~195 while driving. What am I missing ?
 

Coug

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Have you checked with a laser thermometer to see if the radiator is actually heating up? There could be some type of blockage or your new thermostat might not be functioning properly.
 

twisted60

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Have you checked with a laser thermometer to see if the radiator is actually heating up? There could be some type of blockage or your new thermostat might not be functioning properly.
I took the original thermostat out and it still heated up, tested original thermostat, bad, I installed a civi thermostat and it heated up so I then installed an OEM thermostat same issue, I removed the upper hose and started engine to check flow, granted I do not know what normal flow looks like but coolant was coming out.
I guess radiator may be partly clogged, when I had upper and lower radiator hoses off I ran water into top and it came out bottom. Looking in bottom of radiator I did see what I assume may be calcium build up around outside of tubes but tubes looked clear (what I could see).
Yes I have used a laser thermometer, attaching pics.
fullsizeoutput_2301.jpegfullsizeoutput_22f9.jpegfullsizeoutput_2300.jpegfullsizeoutput_22fa.jpeg
In pic 2 I straightened the fins on the oil cooler.
nlGLYXkEQ%iJ8UCH77kG8Q.jpg
Bottom of radiator outlet hose. Don't know if that normal.

I have also installed a different temp gauge out of my M998, a speedhut unit that in 5 deg incriminates.
fullsizeoutput_2309.jpegfullsizeoutput_2308.jpeg
These 2 temp readings were in my driveway, Everything works as it should until I hit the road.
 

twisted60

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The first thing i would buy/test is a BT-500 Combustion Leak Test Kit. This engine loves to blow head gaskets and put the exhaust gas into the cooling system. How did the old coolant look?
Old coolant looked light green, in my post #1 i mentioned I did an eng block test, that was for exhaust gasses in the coolant system, the test liquid remained blue, Just to test the liquid I placed it in the exhaust and pumped the bulb, the blue turned greenish yellow. I do get some bubbles when I first start the truck, I use the block test tube with water in place of the cap on the surge tank and watch some bubbles but then I put the blue liquid in it remains blue. The exhaust out the pipe is clear, it has no color as you'd expect with a blown head gasket or other internal eng issue.
Thanks
 

Mullaney

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I took the original thermostat out and it still heated up, tested original thermostat, bad, I installed a civi thermostat and it heated up so I then installed an OEM thermostat same issue, I removed the upper hose and started engine to check flow, granted I do not know what normal flow looks like but coolant was coming out.
I guess radiator may be partly clogged, when I had upper and lower radiator hoses off I ran water into top and it came out bottom. Looking in bottom of radiator I did see what I assume may be calcium build up around outside of tubes but tubes looked clear (what I could see).
Yes I have used a laser thermometer, attaching pics.
View attachment 851964View attachment 851965View attachment 851966View attachment 851967
In pic 2 I straightened the fins on the oil cooler.
View attachment 851968
Bottom of radiator outlet hose. Don't know if that normal.

I have also installed a different temp gauge out of my M998, a speedhut unit that in 5 deg incriminates.
View attachment 851969View attachment 851970
These 2 temp readings were in my driveway, Everything works as it should until I hit the road.
.
That "calcium looking white stuff" looks like it could be restricting flow in the radiator. Might be worse where you can't see (or not). Di you have radiator shops in Florida? Old time shops that will "boil out the radiator"? It should look like copper and clean. That white stuff doesn't allow the heat to dissipate as well as it should.

As far as FLOW is concerned, if you crank the truck and the radiator is maybe 2/3rds full, you should hear and even see water streaming out of the tubes up high in the radiator with the pressure cap off.

Speaking of radiator cap... PRESSURE solves a lot of things . Can you pressure test the cap? Sometimes you can find a "Tool Loaner Program" at the parts houses like O'Reilly's.
 

Bulldogger

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Looks like you're on the right track for getting it sorted out. If you decide to replace the radiator, Champion makes a nice aluminum radiator that fits the TD rig. There are some threads here on the site about it.

Once you have it sorted out, it's my understanding we should run fleet diesel coolant with additives to prevent scale like that. The one I use is from Peak and is Fleet Coolant "SCA Precharged", for what it's worth.
Bulldogger
 

twisted60

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Thanks all, next is pull the radiator, I found a shop that sounds good for cleaning out radiator, I’ll go by and talk to them and make sure that can do it. I plan on putting Fleet antifreeze in after I get it working.
I tried the radiator cap off my M998 and no difference, still gets hot.


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Mogman

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Check and see how much they charge, I was shocked at how much radiator service has gone up lately, the Champion can be had for under 300 (I found them for $218 shipped and bought several) and the 3 core aluminum has the same cooling capacity as a 6 core copper (the OEM is 4 core)

This is counter intuitive as copper dissipates heat better than aluminum, the problem is the way the cooling fins are soldered to the tubes there is a huge loss in heat transfer, not an issue with the aluminum radiators, works great for me so far up to 435HP in the DuraVee

The Champion part number is CCHVB search for that instead of HMMWV as there are sellers trying to get over $500 for them as Humvee radiators.

I see one on Fleabay for $263.85 shipped from a seller with 100% positive feedback.

I see one seller selling them for over $1000 shipped and he actually SOLD one, geez P T Barnum was right!!
 
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Retiredwarhorses

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Your particular radiator is the early round tube, they are basically garbage to try and repair, the later model uses a flat tube from top to bottom. if you order a new radiator now from MAC, they are the new OEM Aluminum.
Try completely removing the thermostat and test drive it.
 

twisted60

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Check and see how much they charge, I was shocked at how much radiator service has gone up lately, the Champion can be had for under 300 (I found them for $218 shipped and bought several) and the 3 core aluminum has the same cooling capacity as a 6 core copper (the OEM is 4 core)

This is counter intuitive as copper dissipates heat better than aluminum, the problem is the way the cooling fins are soldered to the tubes there is a huge loss in heat transfer, not an issue with the aluminum radiators, works great for me so far up to 435HP in the DuraVee

The Champion part number is CCHVB search for that instead of HMMWV as there are sellers trying to get over $500 for them as Humvee radiators.

I see one on Fleabay for $263.85 shipped from a seller with 100% positive feedback.

I see one seller selling them for over $1000 shipped and he actually SOLD one, geez P T Barnum was right!!
Thanks Mog, is that part number the same for my ECV model (M1152). I’ll look in parts book later. Thanks
 

twisted60

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Your particular radiator is the early round tube, they are basically garbage to try and repair, the later model uses a flat tube from top to bottom. if you order a new radiator now from MAC, they are the new OEM Aluminum.
Try completely removing the thermostat and test drive it.
I did remove the thermostat but did not drive it. I have tried the original thermostat (it was bad), tried civi thermostat that I tested before install (later removed), currently installed is an OEM thermostat.
I am leaning toward new radiator, can I have a leaking head gasket and it not show up with combustion block test ? The blue liquid doesn’t change color.
Thanks
 

Mullaney

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I did remove the thermostat but did not drive it. I have tried the original thermostat (it was bad), tried civi thermostat that I tested before install (later removed), currently installed is an OEM thermostat.
I am leaning toward new radiator, can I have a leaking head gasket and it not show up with combustion block test ? The blue liquid doesn’t change color.
Thanks
.
Not always - but is the engine oil clean?
No milky looking gunk on the dipstick or inside the fill cap?

Generally if the problem is that bad, I would think you would be gathering antifreeze in the oil by now. Might not. Could be that there is a leak straight into a combustion chamber - but even that ends up in your oil eventually.
 

twisted60

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.
Not always - but is the engine oil clean?
No milky looking gunk on the dipstick or inside the fill cap?

Generally if the problem is that bad, I would think you would be gathering antifreeze in the oil by now. Might not. Could be that there is a leak straight into a combustion chamber - but even that ends up in your oil eventually.
Oil looks good, not milky, oil fill cap is clean, no white smoke out exhaust, no blow by (that I can see), runs good, sounds good, just overheats.
 

Mullaney

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Oil looks good, not milky, oil fill cap is clean, no white smoke out exhaust, no blow by (that I can see), runs good, sounds good, just overheats.
.
Clean oil is definitely good news!

Hopefully then a radiator cleaning - or maybe a new one.
Based on other posts just before this - SHOPPING PRICE - seems to be a real key to happiness
 
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