Bleeding Coolant

A

Arthur

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Fellow Frogger
Joined
Jul 28, 2002
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74
Location
Sydney
After replacing the coolant, what is the correct procedure for bleeding air from the system?

Is it start the engine, open bleed screws, wait until coolant comes out, then close. Or do you bleed with the engine not running and applying positive pressure at the radiator filler neck?

It's for a 306 but I assume all cars are the same.

Arthur
 
Your Haynes Manual will tell you.

Basically, you fill 'er right up, start the engine and work your way up from the bottom bleed-screw to the top bleed-screw, in sequence (air bubbles rise in water!). You want the radiator cap on so the system is under pressure - just make sure that the coolant is right up to the cap as you are after all, slowly draining the level down and if the level goes lower than the highest-bleed-screw in your system, you're re-introducing bubbles - basic physics!

i.e. Loosen the bottom-most screw in the system until the fluid comes out the hole in the screw's thread. When no more bubbles come out, tighten fully down and move onto the next lowest bleed screw... ...until you get to the top bleed screw of the system...
 
Do you know where all the bleed screws are? So far I've found the one on the radiator, one just after the thermostat on the housing, one ontop of the head, right before the thermostat, one at the rear left of the engine on a black metal return pipe, and the heater core one under the wipers on the firewall.
 
205 GTI16 said:
Your Haynes Manual will tell you.

Basically, you fill 'er right up, start the engine and work your way up from the bottom bleed-screw to the top bleed-screw, in sequence (air bubbles rise in water!). You want the radiator cap on so the system is under pressure - just make sure that the coolant is right up to the cap as you are after all, slowly draining the level down and if the level goes lower than the highest-bleed-screw in your system, you're re-introducing bubbles - basic physics!

i.e. Loosen the bottom-most screw in the system until the fluid comes out the hole in the screw's thread. When no more bubbles come out, tighten fully down and move onto the next lowest bleed screw... ...until you get to the top bleed screw of the system...
Click to expand...

Thanks for the info.
Will get around to it this weekend.

Arthur
 
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