Well I thought I knew how to bleed the radiator in my 90 Civic Sedan! What I understand you are supposed to do is open the bleed screw and fill until no bubbles come out of the bleeder screw. How do you do that and get the air out of the heater core too without starting the engine. Are you supposed to bleed it while the engine is running? Help!!!! Thanks.

 

Here is how I do it:

Turn heater to "HOT" position.

Remove bleeder screw.

Find some sort of funnel that will fit and seal inside or around the bleeder hole.

Fill funnel with water/coolant and place it in the bleeder hole

Squeeze upper and lower radiator hoses repeatedly until no more bubble come out of the bleeder

Keep water/coolant in the funnel the entire time.


You can also jsyt start the car up with the radiator cap off and heater in "HOT" position and fill the radiator with water/coolant as needed. The air bubbles will make their way out, but I like the funnel method.

 

Don't think I have a funnel small enough to fit in the little hole where the bleeder screw goes. I just tried to just let it run with the heater in the hot position and the bleeder screw cracked open. Bubbles came out off and on for awhile. The heater though didn't even get the slightest bit warm. The radiator cap was screwed down though. I'll go back out and take the cap off and crack the bleeder screw open and try it again that way. I assume if there is air in the system it could take several minutes of letting it run with the bleeder open.

 

Rig something up. Rip the cover off a phone book and make a funnel out of it. Tape it up a bit if you have to. That's the best way I have found. Leave the cap on when you do that.

 

Added confusion. The upper radiator hose is hot and the bottom is cold. What do you think is causing that?

 

eather u got a bad thurmastat or your radiator is cloged. lean the radiator back so u can get ut hand in the front and check if theres cold spots on it.

 

Would a bad thermostat cause the upper hose to be hot and the lower one to be cold? I got this engine out of a wrecked car so I have no idea if the thermostat was stuck in it or not. The radiator in mine is the one that was in it when I got it. Mine had a blown head gasket and I flushed the radiator pretty good with water and got most of the oil out of it I think.