2004 Chevy Tahoe Z71 Overheating Still

[cowboymdr]

This is driving me, and several techs I know, crazy! My Tahoe started losing coolant at about 1/2 gallon every two days with no visible leaks.

• Tested pressure on cooling system and found no loss.
• Put StopLeak into system and saw no change in overheating problem.
• Flushed radiator and saw no change.
• Checked input/output temps on radiator and they were normal.
• Replaced water pump and t-stat, and found water pump was leaking behind the face plate. This solved the leaking coolant problem; however, the truck continues to overheat.
• If I keep the heater on full @ 90 degrees, temp stays normal all day, but if I turn heat off the truck overheats again.
• Block test shows no combustion gasses in cooling system.
• Checked plugs and no fouling or suspicions here.
• Seems to run at normal temp for long periods, but overheats again everytime I go up a hill.

I appreciate any ideas or insight...I am baffled.

 

[lesterl]

Plugged up Cat?

Plugged up radiator?

Collapsed hose?

 

[cowboymdr]

Plugged radiator was the culprit. Thank you for your reply, lesterl.

 

[lesterl]

No problem, sounds like you tried alot of stuff to begin with....

 

[Murdock927]

Hey I have. 2004 suburban z71 and having the same issue new converters water pump went through 2 in one year be thermostat new clutch fan did notice a cold spot on the lower driver side of radiator. No foam in oil no smoke no leaks

 

[tahoesteve666]

Hey I have. 2004 suburban z71 and having the same issue new converters water pump went through 2 in one year be thermostat new clutch fan did notice a cold spot on the lower driver side of radiator. No foam in oil no smoke no leaks

How did you notice the cold spot? I'd like to know the method/approach for future reference.