Cool Lower Radiator Hose? Thermostat?

[yukonsc]

I have a 2000 Yukon w/5.3. I was investigating a pulley noise today and noticed that while the upper radiator hose is hot and the lower hose (connecting to the thermostat housing) was cool. Then to confirm I drove home (20-30minutes) and felt the hose again and it was still cool.

 

The truck doesn't indicate the fact it is overheating however shouldn't the lower hose be hot?

 

Any ideas? - I am not trying to 'look' for problems with the truck.... However if I can prevent one I'd like to...

 

BTW Ambient outside temp 45 degrees

[BBSilverado]

If your radiator is doing its job then the lower hose should be much cooler than the top hose. that is the coolant return back into the engine after the radiator has cooled it down.

[az'03Silverado]

I have a similar question. Why is the thermostat at the water pump inlet and not up top where it usually is?

[GM-Tech]

I have a similar question.  Why is the thermostat at the water pump inlet and not up top where it usually is?

 

For emission purposes. This configuration causes quicker warm up and maintains a higher initial temperature. As the the thermostat opens, a gulp of relatively cool water is taken in and the thermostat tends to close again. That doesn't happen in the old location.

[yukonsc]

Ohh okay.. I was wondering about the thermostat location also... I figured what the heck .. must be working correctly my engine temp stays study - just below the 210 mark... I'll fix it when it is broken...