I just finished plumbing my 5.3, lower outlet on rad to thermostat on motor, upper outlet on rad to upper motor outlet.

So I filled it wither coolent, waited, refilled... until I was pretty sure it was full of coolent. Started the engine and let it idle. The temp guage for the megasquirt which runs off the stock sensor in the head slowly heated up like I expected. My mechanical temp guage is mounted in a little box I made with two outputs which are connected to the two outputs on the water pump for the heater core.(the probe is huge and there is no hole on these new motors for it)

So after a while I noted the mechanical gauge was reading nothing and the megasquirt read about 110F, the mechanical gauges box was cold to the touch. When mega read about 160F the box was still cold and both upper and lower cold. So I turned it off, let it cool and refilled rad.

Started it up again, same thing. I let it go to about 225F according to the megasquirt and killled it. both upper and lower cold to the touch, and the box slightly warm. The water pump is brand new and the thermostat is stock (200F i guess?)

The highest point is the upper outlet(see pic) Is there air bubbles?
Should I fill it from the highest point?

any help would be great!!!

 

anybody???

 

You definitely have air in the system if your upper radiator hose is the highest point. Loosen the hose and let it burp out the air. I'm not quite sure how well it'll work on your setup.