'95 Citroen ZX Aura coolant system pressure buildup problem

[csongoose]

Hi!
I have a '95 Citroen ZX aura 1.6i which is my pride and joy now. Over the last couple months, the efficiency of the engine cooling has dropped, resulting in the fans kicking in. The coolant system had pressure in it, resulting in the coolant coming out of the tank when you took the cap off. The problems started after draining and refilling the coolant system with it standing dry for about 1 month. We suspected a blown head gasket and sure enough, it was blown. After doing a replacement and checking the head for cracks, the coolant system is still not working, it is even worse than before. The hose coming off the top of the radiator is stiff and there is air/steam inside.
The refilling of the coolant system was done on a slope and I could get the coolant to steadily flow out of 2 out of the 3 bleed points of the circuit. The one top of the heater matrix produced a steady flow and so did the one near the thermostat but I couldn't get the one on top of the radiator to produce any kind of flow.
With the engine running, the bleed point on top of the heater matrix produces a steady flow, although no water is coming out on the thermostat bleed cap or the radiator bleed cap. After a few minutes of running, it also pushes out all of the water inside of the tank on the cap if I leave that open.
In normal driving conditions, the engine never really goes above 100 Celsius or below 80 Celsius thanks to the fans kicking in. The car also gets to 90 C insanely fast, which concerns me.
Thanks for any help in advance!

[CitroJim]

These engines, in my experience, are not the easiest to bleed... Along with the TU! I find it essential to get a good flow out of the radiator top bleeder...

You can tell if the system is well bled by feeling all over the radiator - it should be hot everywhere once the thermostat is open... But mind the fan when doing this as if it cuts in it'll hurt! Another good check is to ensure the heater is blowing out very hot air when on full...

If the radiator is not hot all over then there's a big airlock in there.

I'm inclined to think the thermostat might be jammed shut, either because it's duff or it's been wrongly installed or is the wrong type. It's essential a 'bypass' type (with a 'top hat') is used to ensure it cuts off the bypass circuit when it opens else the coolant will just short-circuit through the bypass passage and never flow through the radiator...

But do check too for a choked/blocked radiator as even when cold and during filling with coolant you should be able to get a coolant flow out of the top bleeder, especially if you squeeze the top and bottom hoses to get coolant flowing...

It's vital that all bleeders are fully open when initially filling with coolant...

[wheeler]

Did you use a header tank on the filler to increase the height of the filler?