I just put in a new heater core in my 03 sierra 5.3, and I am looking for
ideas on bleeding it because I keep getting a gurgling sound on accel. I don't
see any leaks but I am going to pressure tomarrow. I think it's just an air pocket in the heater core. I already lifted up the res. to be higher than the heater core inlet lines and let it warm up w/ a few steady revs to 3000 rpm. still not fixed. any ideas?

 

Possible air pocket like you mentioned... I've had good success at filling the coolant system and not getting any air pockets by grabbing the upper hose and squeezing it while sorta pulling it downward. I put a "funnel" (small washer fluid bottle that was cut and made into a funnel) in the radiator fill neck, and fill the coolant until it's about 1/4 to 1/3 of the way up, then grab the upper hose and squeeze and pull downward...the coolant will bubble and burp and go down into the radiator. I keep doing this until the coolant no longer burps, then start the truck and do a normal process of letting it run until the thermostat opens and the coolant sucks down, then filling it to it's proper level. I then drive the truck a bit, let it cool down, and recheck the level. So far it's been perfect every time. I used this method when I did my cam swap, and again when I did my 05 efans and 34" radiator, and also when I was a Toyota tech (different monster of course, but also prone to air pockets if the coolant is not burped when filled). Works for me

 

thanks, yea I have a coolant fill funnel at work but I don't have the threaded adapter.
I'll try messing with the upper hose more, but I'll propably buy or borrow that adapter, that should help.

 

Like BUD said.. More then likely it will bleed out on its own, but what he said will get alot of it out..