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But in my Helm manual, it definitely calls the thermostat housing "Outlet, Water". Not to mention that just by looking at that picture, it's not possible. For coolant to even flow into the water pump via hose #1, the thermostat would already have to be open.
You can also confirm (when bleeding the cooling system), that the lower hose (#14) heats up before #1. And hose #1 only heats up AFTER the thermostat has opened.
Now, correct me if I'm wrong, but I think GM labeled those hoses wrong.
Heat isn't going to transfer through that much water sitting still in the Radiator. When the Thermostat opens..the cooler water goes into the Engine and the warmer stuff finally cycles through.
Same way with the LS1.
But in my Helm manual, it definitely calls the thermostat housing "Outlet, Water". Not to mention that just by looking at that picture, it's not possible. For coolant to even flow into the water pump via hose #1, the thermostat would already have to be open.
You can also confirm (when bleeding the cooling system), that the lower hose (#14) heats up before #1. And hose #1 only heats up AFTER the thermostat has opened.
Now, correct me if I'm wrong, but I think GM labeled those hoses wrong.
As Merv said, neither main radiator hose is going to warm up until the thermostat is open and water can flow.
If you want to call something documented "wrong", I would say it is the label on the thermostat housing that you pointed out. I think the parts book is entirely correct.
Last edited by shbox; Feb 5, 2010 at 05:20 PM.
As Merv said, neither main radiator hose is going to warm up until the thermostat is open and water can flow.
If you want to call something documented "wrong", I would say it is the label on the thermostat housing that you pointed out. I think the parts book is entirely correct.
That and the Bleeder Screw is there cause that is the final point that water travels to.
The picture up at the top shows cool water flowing from the radiator into to the water neck that holds the thermostat and then into the engine. Thats my point about the bleed screw and what I was asking shbox about in his picture. cold water that flows that way into the pumpshould cause the thermostat to not open. All of the stuff I read in the manuals says that the water neck that holds the thermo is the outlet for hot water from the engine to the radiator.
If I am wrong by all means I am soory for dragging this out.

At first I thought it was the way you are saying..but then I thought about it and it made sense.
That Neck is the point where the Water is let in to the pump..as in it flows out of the Radiator. If you take it apart you will see the actual functioning part of the Thermostat is in the Waterpump, and therefore in the hot water. As it reaches it's temp it opens up and lets cooler water in..then when it evens out it closes, and re-opens when necessary.
It's the same way with the LS1..that is what made it make sense for me when I thought about it.
That Bleeder is there cause that is the final point of the Water travel through the Engine.
Make any sense?
The picture up at the top shows cool water flowing from the radiator into to the water neck that holds the thermostat and then into the engine. Thats my point about the bleed screw and what I was asking shbox about in his picture. cold water that flows that way into the pumpshould cause the thermostat to not open. All of the stuff I read in the manuals says that the water neck that holds the thermo is the outlet for hot water from the engine to the radiator.
If I am wrong by all means I am soory for dragging this out.
You looked at two diagrams that called the the thermo housing the outlet and you got hung up on this. Every other piece of documentation says it is the inlet.



