Air Bleeder Screw

Hey guys, i just had a quick question, with the bleeder screws for coolant, can i just loosen the screw with car off and cold? or does car have to be on? will it piss out excess air in the system? Thanks

Just to double check, these are what the bleeders look like? Its a diffcar but i jus found this pic. http://shbox.com/1/bleeders.jpg

I'll usually open the bleeders with the engine off while refilling the radiator to evacuate air. Then tighten back down warm engine to operating temp, and bleed 3-4 more times, while running.

No fluid will spit out will it? And shud i loosen both at same time? Then turn on and do again?

I loosen both, then pour until antifreeze comes out one of them. I shut that one off and keep filling until the other seeps fluid. Then top off the radiator. Then bleed it running.

EDIT: I notice your bleeding an LT1. These can be a headache to bleed. You may need to bleed it again in the very near future to get the rest of the air out...Just make sure it's warmed up all the way..

K i just loosened one of the screws, antifreze was coming out, i left it for a second but it wasent stopping, does this mean theres air in the system? do i have to let it bleed until it stops then top it up, or will it just keep leaking until theres no coolant left? I tried the main screw i seen, the one that has sticker that says notice: dont vent while engine running. thats one of them right? So is it normal for it to spew out, is there air behind it? Thanks

Edit: what is LT1 and why is it a headache to bleed?

Just bleed it long enough to remove the air bubbles, then retighten. I usually start with the bottom(mounted on thermostat housing) screw, engine off. Stop pouring coolant when antifreeze begins to seep out the bottom screw, then tighten it. Then loosen the top screw, and repeat the process. hen start the engine, allow engine to warm up fully(keep an eye on the temp gauge, it might get hot). After it has warmed, slowly loosen the bottom bleeder until there's a stream of antifreeze(and no bubbles) running out. Tighten it and go to the top one, repeating the process. BTW, an LT1 is the engine used in many camaro's, firebirds and corvettes, to name a few. It's a 5.7 Liter that utilizes reverse-flow cooling, which means the coolant flows backwards compared to other vehicles(LT1's flow into the heads, then on to the block, others always flow to the block first). I guess this causes air to become trapped more easily. If it gets hot on you after driving it for a bit, just pull over and bleed it again. It's gonna take a few times to "burp" the system good.