Overheating

[Michelle Gomez]

I have a 2006 Silverado with a 4.8 swapped to a 5.3  ,all works well sounds great but is overheating after 40 to 60 minutes. Water pump ,thermostat has been changed fresh coolant add. Cant figure why overheating is happening. Any ideas?thank you in advance. 

[Mikebtte]

Are the fans coming on?

[Michelle Gomez]

Yes.

[BlancoSilverado]

Because i do not know, is the radiator the same size for both motors?

Was there rust in the coolant that you swapped out? if so then you could have a plugged radiator?

[Michelle Gomez]

Ok thank you ,no rust was seen ,but will do a flush anyway.

[Mikebtte]

have you confirmed it is overheating by checking the coolant temp sensor has not failed and is reading wrong. 

[txab]

Got all the trapped air out of the system?

[Formulabruce]

 

More than likely your serpentine belt is on wrong, and water pump is going the wrong direction...

[swathdiver]

22 hours ago, Michelle Gomez said:

I have a 2006 Silverado with a 4.8 swapped to a 5.3  ,all works well sounds great but is overheating after 40 to 60 minutes. Water pump ,thermostat has been changed fresh coolant add. Cant figure why overheating is happening. Any ideas?thank you in advance. 

Was this engine tested and checked out before installation?  

[davester]

and you've felt the radiator hoses, when the engine is hot, to verify that coolant is flowing through the radiator?

[MaverickZ71]

22 hours ago, BlancoSilverado said:

Because i do not know, is the radiator the same size for both motors?

Was there rust in the coolant that you swapped out? if so then you could have a plugged radiator?

AC Delco online catalog lists the same radiator for both engines, part #21650.