Cooling system bleeding help.

[VeiRoN]

Hi there,I need a little help here,currently trying to bleed a 1.1 Saxo.

I'm following the Haynes manual so I let all the old coolant out and flushed both radiator and engine side.
Next I put an header tank with about 0.5 of coolant in,bleed the first rad screw,the one to the left on the engine and last the thermostat one.

Started the car after a while however the level in the header tank does not seem to change even when the fan came in so there must still be an airlock somewhere,shortly after the fan all the coolant quickly raised and come out of the header too quick for me to drain it in time so i shut the car off.

While doing this I noticed the the top and the hose where the screw cap is on the left on the engine are hot instead the bottom radiator hose is cold and i can see the radiator plastic bleed screw slowly letting coolant (along with bubbles) out even when correctly closed in position,this of course was fine until after I opened it and it's the first time this happens to me.

Am i right assuming that this is preventing me from bleeding the system properly? or is there anything else i'm doing wrong? Also it seems a little of a problem getting hold of this part any idea where i can get the replacement bleed screw as I couldn't find anything on ebay and EuroCarParts.

Many thanks.

[stevo67]

The way I do it and it works for me is just bleed using the nipple to the left and the back of the engine.The other bleed nipple does it resemble a tyre valve cap?because i've had a nipple cap fly off before under pressure and used a tyre valve cap and it's been fine.

[VeiRoN]

Yes I'm also using that one together with the other two,these two are fine it's just the rad plastic bleed screw that's slowly letting coolant out when engine is running even when closed so I believe it is messing up the bleeding process,I'll try and see if the one from my VTS fits.

Are you bleeding trough the tyre cap bleed screw only when the engine is off and cold?

[Manu]

I park up and down so the remaining air bubbles do the same. Fill it all up while the engine is running, and bleed with hot engine off. Obviously carefully so you don't burn yourself. Takes a few attempts to bleed it all out.

[Gandi699]

you should use a "header tank" as the filler neck is not the highest point, plenty of guides on how to do it

[VeiRoN]

I used an header tank,see 1st post.

Anyway,I believe it's fixed now,did the usual bleeding process with engine cold,let it run until fan came in,however the radiator bleed screw was still leaking coolant out even with a new o-ring,much less but than before but still leaking,though after I bled a couple of times trough the thermostat bleed screw it eventually stopped and remained dry trough 3 fans cycles and also a short drive.

It might be something to do about pressure due to excessive air still trapped inside? Just a thought,anyway seems to be sorted now,will keep checking it in the next few days.

Bleed screw that was previously leaking:

http://i.imgsafe.org/21e22c1.jpg

[stevo67]

Yes I'm also using that one together with the other two,these two are fine it's just the rad plastic bleed screw that's slowly letting coolant out when engine is running even when closed so I believe it is messing up the bleeding process,I'll try and see if the one from my VTS fits.

Are you bleeding trough the tyre cap bleed screw only when the engine is off and cold?

I take the car for a run,get it up to temperature.Then switch off and slowly unscrew the back bleed nipple,leave it like that for a few mins then remove completely.Usually after this there is hissing sound and once the water starts coming out free of bubbles I put the nipple back on.:drink::y: