No flow of water in new LS3
 

Finally got my LS3 427 started but the water is not flowing through the block. All parts are new to include the thermostat and a Dewitt radiator. Temp rises but radiator is cold. This is the first few starts, so I only run it for a minute or so since the engine temp rises. First thing I think of is the thermostat but I remember seeing posts about getting the water to initially flow. thanks

There's no special tricks here. If there is coolant in the system a bad thermostat would keep water from circulating. I bet you're not allowing it to get hot enough for the thermostat to open.

temp is going just past 210, these are the first runs and the radiator is full, has taken about 4 gallons. Fans tied to the Dewitt radiator sensor, temp sensor to the block. The temp rises quickly. Do I need to fill the block from the top hose as well? Again radiator and water cold.
Kevin
This was in an article is Super Chevy so I will try this I do remember this.

17. We are not ready to fill the system just yet, as you may have noticed there is no intake manifold on the engine. We will give you an update once we get the car running. Be Cool has very detailed instructions on how to properly fill the system and its too detailed to fully explain here, but here are a few things to note. Jack up the nose so the radiator is the highest point in the cooling system. Fill the radiator with the engine off. Wire the fans to run all the time, and if so equipped turn the heater on high. Then start the motor with the radiator cap installed in the loose position. Run the vehicle until the thermostat opens. When the fluid suddenly drops in the radiator, add an additional 2-3 quarts. You may need to repeat this cycle, but once topped off the second time tighten the cap. After a few heat cycles check the level one more time and you should be good.


Sources



Be Cool
Essexville, MI 48732
800-691-2667
»www.becool.com

I'd bet there's air in there. The notes you posted should get you going. I squeeze the hoses a bit too as it warms which seems to help.

There is a funnel that you can buy specifically to fill the radiator. However being low would not prevent circulation. If you pop the cap and keep topping it off, the system will fill. You have a t-stat issue if it's burped and filled.

The procedures mentioned are to get the air bubbles out. It's possible the sender is reading hot due to this and the water is actually not that hot thus the t-stat is not opening up.

So the question is how long to I let it run at that temp before shutting it down. I have filled the radiator a few times to the top so it is going into the block some any way. The heater hoses are warm. So there may be air in the system thus the higher temp reading on the gauge? Thanks

Can you incline the nose of the car? This will force bubbles to the highest point. Do that, pull the radiator cap and let it run. Warm heater hoses tells me the pump is working.

I concur and will try that tonight or tomorrow. Thanks

210 isn't hot. Let it run.

It blows through 210 so that's why I shut it down. I am thinking it an air pocket

Its not elevated enough but the upper hose is getting warm, bottom hose still cold but the water in the radiator is warming up as well. Very frustrating

tried elevation and also ran with heat on, heater hoses warm, lower hose cold, upper is warm, temp past 210 shut off. I think I will pull the thermo stat and test it. :bang:

I pulled the thermostat and started the car, same result except I got water through the lower hose. There must be a nasty pocket by the water jacket or????? Thanks

One thing I usually do with new stats, is drill a little air bleed hole in them to help with those issues :)

Thanks, I will test the sensor today

The last thing I thought was bad was the gauge and sure enough, before the water reached a boil the gauge went to 250. Time to call auto meter, that was a hateful two plus weeks. Thanks I will let you know how the new gauge works out.

Are you using the autometer temp sensor? It won't work with the the stock LS sensor that the ECM is using. You need two sensors.

Don

I am using an auto meter temp sensor where did you come up with two sensors? Thanks

What temperature sensor is your engine controller using? Are you using the GM controller?

Quite often guys use two sensors, one in each head.

Don

I would think you have a factory sensor on the driver side forward in the cylinder head. I run the auto meter sender in the passenger rear part of the head. If I recall you said the fans sensor is in the radiator.

gotcha

Well I checked even further about the gauge and on Auto Meter's web site they list the same symptoms I was having to a bad ground. Long story short it is a bad ground. I changed the ground and the gauge stayed at 210 while the water was boiling. Thanks for all your help, I will know tomorrow or so when I crank it back up.

Note to Badazz I run the sensor on the ps side in the rear as well.

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