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Discussion Starter #1
So long story short engine overheated not sure for how long. Cooled truck down filled back up with collant and tried to go down the road over heated again and blew coolant out overflow. Towed truck home thought blown headgasket so tore engine down and put back together. Filled with water and let run to burp cooling system. Got hot air from heater things were looking good and then shortly after overflow started overflowing again cooling system is building pressure. I didnt see any cracks anywhere when everything was apart but i am now leading towards a cracked head or block. Does anyone have a good solid test to figure out if the block is cracked or a head is that can be done at home?

Key points

Truck over heated unknown time

Blowing coolant out overflow and overheating

New headgaskets installed

Truck overheating and blowing coolant out overflow after new gaskets
Please help asap i have to leave town for work in just over a week
 

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Is there coolant in the oil and does it smoke? Stop throwing parts at it and get the system pressure tested..

Also check to see if the thermostat is opening
 

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Discussion Starter #3
There is zero oil in coolant or coolant in oil and no white smoke out exhaust and i am looking for a test and not looking to throw more parts at it
 

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Buy a pressure tester and pull all the plugs. You'll hear it. It can be just a warped head or block. In that case one or the other will need to be milled. At that point might as well go with a rebuild or swap another engine... Let us know what you find during the pressure test.

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Are you loosing coolant? As of now there's no tell tale signs of it using any coolant other than the coolant overflow...
 

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Discussion Starter #6
Currently after doing headgaskets the only issue i have is coolant flowing out the over flow and it getting warm and getting a pressure tester is on my list for today
 

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Discussion Starter #8
I will pull it out today and see if it is working cause it has been on my mind since last night cause when i firat went to burp the motor it didnt seem to be working and i had to squeeze the upper radiator hose to get it to open and i only say yhus cause i could grab the heater core hoses and they were cold but after squeezing the upper hose a few times i was able to get hot coolant to the heater core maybe it stuck shut again after that cause the heater did seem to lose some heat
 

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Very well can be simple as a thermostat. After swapping to head gaskets it would be assumed that you did swap the thermostat. That could be the root cause of your whole overheat to begin with.

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Discussion Starter #10
I had just put a water pump and new thermostat in 3 months ago so i was thinking it was still good. So didn't pick up a new one since you don't have to remove any of the front accessories. and the actual cause for the first over heating was the fuse to my electric fan had popped and they didn't come on while I was sleeping in my truck with it idling. I had just done the exact thing the night before in south dakota for 2 hours with zero problems. So between south dakota and montana something caused the fuse to go and i will be searching for that problem after i fix this one.
 

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Discussion Starter #11
And normally in the past anytime i have ever had a vechical over heat for any reason i have swapped the thermostat no matyer what but this time i didn't and not following that may have bit me in the ass
 

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I would look into replacing the fan motors or assembly because they don't just pop likely one of them doesn't work or will fail again. Also clean the radiator front side with the water hose or something I cleaned mine on my 14 and it was filthy. Cooling is no longer an issue as I rarely ever see 200 degrees.

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Discussion Starter #13
They seem to be running pretty loud so it has been on my mind that they have possibly been on their way out and with the blown fuse i wounder if it was cause of them pulling a larger draw they are factory fans from off i want to say an 05 when i swapped in my 6.0 i switched to electric and got them out of the junk yard
 

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Discussion Starter #15
Yes i have flushed the system many times over the years including 3 months ago when i did the water pump and thermostat and no im not talking just drained and re filled. Any time i have done a water pump when i swapped my motor and also when i replaced the heater core and even a year and a half ago i did it cause the truck more or less sat for almost 4 years before that cause I was always driving my duramax.
 

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Discussion Starter #16
Well took thermostat out and after the truck idles for a while ran into same problems large amonuts of air comeing out overflow tank and pushing coolant out and this is not like a bubble pushing out cause the coolant shoots up like a geyser and i cant get the heater core to bleed out air and heater is only blowing cool air
 

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Sounds like a a bad head gasket is pressurizing your coolant system.

You really should have had your heads checked for warping when you had them off.


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So long story short engine overheated not sure for how long. Cooled truck down filled back up with collant and tried to go down the road over heated again and blew coolant out overflow. Towed truck home thought blown headgasket so tore engine down and put back together. Filled with water and let run to burp cooling system. Got hot air from heater things were looking good and then shortly after overflow started overflowing again cooling system is building pressure. I didnt see any cracks anywhere when everything was apart but i am now leading towards a cracked head or block. Does anyone have a good solid test to figure out if the block is cracked or a head is that can be done at home?

Key points

Truck over heated unknown time

Blowing coolant out overflow and overheating

New headgaskets installed

Truck overheating and blowing coolant out overflow after new gaskets
Please help asap i have to leave town for work in just over a week
Well documented problem with 5.3 engines from 1999 on up. You'll most probably need to change the offending head. This is caused by bad castings. It usually starts to happen after 4 to 5 years of use but has been known to crop it's ugly head earlier or later. GM has divorced them selves of the problem. If you buy used heads have them magnafluxed before you pay for them. If ypu're looking to get a couple of years out of the truck you might try one of the common head sealers.
 

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Well documented problem with 5.3 engines from 1999 on up. You'll most probably need to change the offending head. This is caused by bad castings. It usually starts to happen after 4 to 5 years of use but has been known to crop it's ugly head earlier or later. GM has divorced them selves of the problem. If you buy used heads have them magnafluxed before you pay for them. If ypu're looking to get a couple of years out of the truck you might try one of the common head sealers.

That's been discussed on the other thread that exists for this... also its a 6.0
 
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