ascastil

Ok so I just had radiator repaired and pressure tested and I installed it. While I was at it I went ahead and through on a new water pump. I have read and studied Shoeboxs how to on bleeding the system, but it seems the air is never completely gone, it just keeps coming out the bleed screw on the top hose, I think the one that goes to the heater core. How long does this process take? I even filled it the first time where the thermostat goes to try and lessen the amount of air that gets in.

ascastil

Well, Ive had the car running for 35 minutes now. Still air coming out. Every once in a while Ill get a solid stream of coolant, then itll start burping out air again. So do I just sit tight and be patient or does this seem wrong?

grabbem88

No my car had the same issue I ended up jacking the car up really high
Turned my heater on and opened bleeder then squeezed both hoses to and from heater core
I even shut it off and let it cool down with everything open and came back then bled it one more time to be sure

shoebox

Using the procedure on my site, I have never had any trouble and rarely is there any air to bleed out if you open the bleeders when filling (like the instructions say).

ACE1252

This.

You don't need to raise the front end and all that......

This is what I do...and it is going to mostly mirror Shoebox's instructions.

First, the way I fill the system can overflow the radiator, because I do run it with the radiator cap off until fully warmed up. So get yourself one of these....

Lisle 24610 Spill-Free Funnel

• GM recommends two cooling system sealing pellets be put into the system when fully drained. I use them, but others don't. If you want to, here is the GM P/N 3634621.
• PROTECT THE OPTI FROM COOLANT WITH TOWELS.
• Open both bleed screws.
• Fill the overflow reservoir to full hot.
• Fill the system until a steady stream of coolant comes out each bleed screw.
• Close each bleed screw when a solid steady stream develops from each and don't touch them again during the process. There is no need to go jacking around with them again.
• Fill the radiator almost to the top and put the spill free funnel on the radiator.
• Turn the interior heater to full hot and interior fans wide open.
• Fire up the engine(radiator cap still off the radiator, do not put it on until the end of this process).
• Let it get up to temp, but don't let it get over 200*. If it gets to 212* it's going to boil and get messy(as the cap is off)....ask me how I know.
• As the engine gets warm, you are first going to see the coolant level rise. This is where the spill free funnel is worth it's weight in gold....otherwise you would have to fill the radiator half full, and even then, I've had it overflow on me before the thermostat can open.
• When the thermostat opens, the level will fall like a rock....add coolant to get the radiator back full. I fill it so that the funnel is 1/4 to 3/8 full.
• As the engine is getting warm, blip the throttle. This can help the coolant flow get rid of any trapped air.
• Let the temp get to around 190*...then shut off the engine. Let it cool down just a little...say down to 160* or so)
• Remove funnel, top off the system if necessary, put the cap on the radiator, and you should be done.
• Over the next couple of days, before you fire the car up(engine stone cold) check the radiator level and reservoir level(full cold mark or couple above full cold). Make sure the reservoir is staying consistently at the same level when cold and make sure the radiator is full. If it's a little low, top it off....but at most you should only have to do this once or twice. Most every time, I never have to add any. If you continue to have to top off the radiator/reservoir level, then you've got a leak somewhere and must find it.
  

my1994z28

Thanks ACE,for the funnel info..

andysc

What I do is open both bleeder screws, then remove the thermostat cover, then the thermostat. I then use a funnel and pour mostly distilled water into the engine block. I keep a good eye on the water/coolant going into the engine. You should be able to just be able to hear air coming out of the bleeder screws. Once it fills almost to the top of the opening for the thermostat, I replace the thermostat and then the housing. Once all hoses are tight, I put a rag around the bleeder screw closest to the engine, then fill the radiator with mostly anti freeze, once full I install the radiator cap. I then start the engine, wait for it to warm up, then watch the bleeder screw closest to the engine. Once coolant come out of it constantly, I close it, then wait for coolant to come out of the other. I watch the temp gauge, but have never had a problem doing it this way. If you don't fill the engine, then it heats up to boil over before the thermostat opens. The way I just described will be the easiest way to bleed your lt1 coolant system.

hth

andy schuck

PoormansZ28

Aye, thank goodness for an electric water pump makes getting coolant in that much easier.


I remember having the same problems though.

I first filled the coolant in the WP area where you insert the thermo till it was full, and then I put the rest in on the radiator. Turned the motor on and bled some air out then turned it off and let it cool. Checked the radiator cap and filled it some more wash rinse and repeat until the coolant stayed in the radiator. If you have that much air still in your system you probably need more coolant.

ascastil

Thanks for all the responses guys. Ill be giving it another go round and let you know how it goes.