Ok guys, I need help here. I got my LS1 running a few days ago but it won't cool. I went to an SLP 160 thermostat and that didn't help. I put on a new waterpump and that didn't help. I have the small, 1/4", line that runs between the heads hooked to a heater hose. Does it need to be hooked into the radiator somewhere? The radiator is also brand new. Water never even tries to start circulating. Anyone got any ideas?

 

How are you filling it with coolant? Through the radiator or the top hose? LSx`s need to be filled via the upper hose into the engine block. Which heater hose did you put the head bypass into? I put mine into the 3/4" hose

 

Just a few minutes agi, I moved that hose to a small port in the radiator tank. That didn't help either. I will try to fill the engine through the top hose next.

 

Filling it through the top hose worked. Thanks for letting me know that. Know I have a waterpump I didn't even need.

 

Hope you didn`t run the engine empty for too long. I did the same kinda thing the second time I filled my engine, I remembered and filled it through the top hose the first time. Then after I changed the radiator I filled it through the radiator, started the engine, and I`m standing there for about 2 minutes going WTF theres no flow through the radiator took about another 30 seconds for me to realize what I did

 

hmmm...that is news to me. So if you fill it through the top hose how do you know when you have enough coolant? When it starts coming of the hose or what?

 

Yep, you fill it through the top hose untill you see coolant somewhere in the hose, then put the hose on and fill the radiator. Start the car and wait for the thermostat to open and top the radiator off just like any other engine. You have to fill it through the top hose because the thermostat is in the lower intake hose, the thermostat will not let coolant flow into the block from the radiator untill the engine warms up enough to open the thermostat, and the thermostat will not open unless it has warm coolant against it.

 

I filled it through the radiator, but I also detached the coolant vent tube. I would run the car and gradually put more fluid in until it started coming out the coolant vent tube. If its coming out of there, then you know theres coolant circulating in the engine block. (at least I think, my engine cools fairly well) However, I think Gbody's way is just as easy.

 

thanks G-Body....I am always learning something new here. It makes alot of sense now after the whole thermostart location thing.

 

So how would you go about flushing the system??

 

Hmmmm, never really thought about that until now . I have flushed my car a couple times already, used the same method as with old SBC`s (The "T" in the heater hose, open the radiator drain and the cap) but now that I think about it the murky orange coloring does keep coming back even though I am running green antifreeze. Mabey the cold water going into the heater hose was causing the thermostat to close and I am not getting a complete flush?
Anyone? now that I think about it I am kinda lost