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soot junkie
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194 Posts
Discussion Starter #1
I am working on an 04. The heat hand is reading normal. The top radiator hose is hot as is the t-stat housing. Both heater hoses are hot, but the bottom hose and the radiator stay cold. The coolant system also stays under pressure, even after a 15 minute drive it will still not circulate. I'm not real familiar with Duramaxes, so any help is appreciated.
 

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TDG Mafia # 81
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1,903 Posts
The lower radiator hose should be cold, or cool for the most part as it is the feed for the cold side of the water pump. But a 15 minute drive barely gets my needle moving on my truck, might want to take a longer trip and see if the coolant is boiling out of the surge tank. But if there is coolant in the system and it isnt losing any with the guage in the normal operating range while driving, then more than likely the system is ok.

Just my 0.02 worth,
Tony
 

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BUG JUICER and
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1,239 Posts
You really haven't stated your problem, everything you have described is normal. In the winter, under light load, only one stat opens, and then only for a squirt at a time. The motor needs very little cooling in these conditions.

Some folks in the northern tier, have a hard time even getting to thermostat temp, after an hour. The radiation and conduction losses are more than sufficient for cooling.

With so little coolant flowing through the rad, it is near ambient temp on the bottom, after being cooled.
 

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soot junkie
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194 Posts
Discussion Starter #4
Thanks for the input. The owner brought me the truck saying it is loosing coolant. It builds up pressure and blows it out of the overflow tube when the tank is filled to the proper level. Once it gets down a little it doesn't loose anymore. If this is normal just let me know. Thanks
 

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Senior Member
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3,939 Posts
That actually sounds like the headgaskets are starting to go....

Some pressure in the overflow is normal. Excessive pressure means headgaskets. Does it stay pressurized for a while after running?
 

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soot junkie
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194 Posts
Discussion Starter #7
I have only drove it once, but it was still pressurized after I got back. The day it was dropped off it set overnight and the next day it still had a good bit of pressure. Could I check the oil cap for more than usual blowby to check for bad head gaskets,or do these motors do that.
 

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Senior Member
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My best advice? Call Eric Merchant. Only indicator I know of is the pressurized coolant tank. And what you describe is dead-on how it shows.
 

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TDG Mafia # 81
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1,903 Posts
Tom is on the money, my truck had the exact symptoms, and I talked to Eric. Coolant was disappearing through the overflow, excessive pressure, and heat through the vents was spurradick. I only had my truck three hours when I first discovered the problem. After a few phone calls and a few weeks, my truck is like new, and runs strong!

Tony

PS, have the heads and injector cups checked! Mine also had a leaking injector cup, they replaced the seals to that also. And replace the glow plugs while its apart, much easier now than later.
 
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