Duramax Cooling

guffey24

guffey24

Well-Known Member
Joined
Jun 7, 2006
Location
Hendersonville, NC
ok so I bought a 2005 Duramax cheap because it needed some work, guy said it might need a radiator or a water pump he wasnt sure but something was wrong in the cooling system, I bought the truck thinking I could spend a little money on it and have a nice truck

after reading on several forums I am confused and thinking the truck may have worse problems than I thought

symptoms

low coolant light comes on, coolant is coming out of the surge tank overflow tube, you can fill it up and its good for a couple days

truck does not overheat stays right around 200 degrees, no coolant and oil mixed, no white smoke, but the system stays pressureized even after the truck cools down, drove it all day yesterday came home parked it and coolant comes out of the overflow again, big puddle under the truck and the low coolant light comes back on, fill the reservoir back up drive the truck to the store come back home everything seems fine again

go out this morning try to open the reservoir and its still under pressure and starts blowing coolant out of the overflow tube, upper radiator hose is hard,

so am I looking at bad headgaskets even though the obvious signs dont point to it?
Air in the system that I am not seeing?
radiator cap?, thermostat's?
radiator, water pump?

I dont want to throw parts at this truck if it dont need it

Also if it is head gasket problems, who would you recommend as I dont have the time to tackle this?
pricing?
 
The obvious signs do point to headgasket! These trucks do not fail like you would typically expect. This sounds like a common a lly headgasket failure. For starters it would be ideal to verify by bleeding the system and replacing the cap. Combustion gasses may not be detected even if the gasket is blown and that's a characteristic that pretty common to the duramax. Worth mentioning that it does have a egr cooler. They rarely have issue. You could test that by putting a gauge on the cooling system and seeing if pressure rises faster with the vanes commanded to the closed posistion.
I know most shops (including mine) are not interested in doing a job like this. Small shops don't have much profit potential in it. Might look at the dealership. I know Olee (704-855-2679) had done one recently but I'm not sure if he'd want to do another. Also there's another gentleman in Lenoir or hickory that's been doing some. the advantage to the dealer is a warranty and gm backing the job.
 
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ok thanks for the info

after reading above and more forum reading I found the little bleeder screw on the thermostat housing, it had a ton of air in it, is that normal at all?

after bleeding the air off and driving it around it seemed normal again, not overheating at all, no coolant blowing out of the surge tank line

so in the morning, I am going to check the upper radiator hose and the overflow surge tank cap for pressure, if it has pressure I am going to replace the cap and see what happens
 
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