Over heating problem

[Brian Lancaster]

I am having trouble with my 2004 1500 5.7 while driving my trucks temp will spike over all the way to where my check gauge light comes on. Some times it stays high and some times it will drop back down. I have changed the t stat water pump has been changed new radiator. The motor was rebuilt 2 years ago. I am thinking it is the fan cluch or cracked block or head gasket.

 

[crazykid1994]

I’d say check fan. Have you made sure the system is completely void of air?

 

[ThunderMug95]

Whats the coolant look like? Losing any?
Whats the oil look like? Chocolate milk or just oil?
Assuming new hoses went in with engine rebuild....
Not saying it is, but there could be a blockage in cooling system/fitting/hose or even air trapping in the motor. If it were me, I’d do an oil and coolant change ASAP. Really burp that radiator. If no signs of cross contamination in fluids then your problem could be as minor as a temp sending unit, could be sending false data to computer or even the Tstat is failing, its mechanical device, they fail...
this is where I would start at least. Best of luck.

 

[Brian Lancaster]

I am losing coolant when the engine temperature gets all the way over the hot. The oil looks good and was changed less than 1k miles ago. Yes new hoses went on at the time of the rebuild. New coolant was done when the radiator was put in. I had the cooling system flushed before the new radiator was put in. When the temp gets down from going way over to hot you can see the t stat working and keeping at a mid range.

 

[crazykid1994]

Does the mechanical fan free spin or have a little resistance if you try and move it? Truck not running of course. Truck on and warming up is the fan spinning? Does your exhaust smell sweet? If coolant is leaking into the cylinder you should be able to pull your plugs and see one wet and you would most likely have a small misfire. When the truck is running can you squeeze the upper radiator hose? Does it get warm? Are there cold spots on the radiator?

 

[Spoonsize]

Might be an airlock. Park it overnight on a very steep incline, steeper than ever before.

 

[Logan Klein]

I am losing coolant when the engine temperature gets all the way over the hot. The oil looks good and was changed less than 1k miles ago. Yes new hoses went on at the time of the rebuild. New coolant was done when the radiator was put in. I had the cooling system flushed before the new radiator was put in. When the temp gets down from going way over to hot you can see the t stat working and keeping at a mid range.

This sounds like a fan clutch that's failing to engage sometimes. It's an easy, cheap fix. You could also attempt to bleed the cooling system of air. Usually when replacing the fan clutch or any accessory drive components, I would replace the serp. belt and check all pullies for play, cracks, or excessive wear on the surface the belt rides on. A way you can also keep that engine temp down is by installing a thermostat that "clicks" at a lower coolant temperature. Seeing as though your engine was rebuilt, it seems unlikely to be a crack in the block or a bad head gasket. Though overheating these 4.7's will absolutely warp the aluminum heads, which cost a fortune to have replaced/resurfaced. Just be smart and don't drive the truck around anymore until you solve the problem, you don't wanna find out you warped those heads by overheating the engine.

 

[Brian Lancaster]

I have a miss fire on Cylinder #1

 

[madtrucker2016]

I am having trouble with my 2004 1500 5.7 while driving my trucks temp will spike over all the way to where my check gauge light comes on. Some times it stays high and some times it will drop back down. I have changed the t stat water pump has been changed new radiator. The motor was rebuilt 2 years ago. I am thinking it is the fan cluch or cracked block or head gasket.

Maybe the re builder put the wrong head gasket on could be blocking a port so no water is going to that part of block it happened to me on a jeep Cherokee