hi all

the cooling system on my xr8 wont pressurise
i had it running in the shed for 20min or so with the heater on full heat to bleed any air out and the top radiator hose didn't go hard, seems like there isn't much coolant in the top hose cos when i squeeze it i can hear air going into the header tank through the small hose that joins the tank and top hose.

what could be the problem? stuck thermostat? had the car in the shed idling for 20 odd min and it didn't get any warmer than normal operating temp, thaught it would have run warmer if the thermostat was stuck closed.
i cant see any coolant leaks so that should rule out any air leaks aswell.
what could be causing this? im realy hanging to drive my car. poor thing hasnt been out the shed at all this summer

If you haven't got any coolant leaking anywhere, I would be thinking you have a buggered header tank cap!

If your thermostat was stuck closed you would know all about it...... After 20 minutes you would be calling an engine builder to re build your overheated seized motor!!

Better to have a stuffed cap I think!!! haha

yeah thats what i thaught, 20min with thermostat stuck closed and she should be prety hot.
i was thinking cap but i have a stant cap (think thats what it is) and its not that old but i guess that doesnt mean it couldnt bugger up.

any other ideas before i order a new cap?

First of all make sure the cooling system is full, then have a look at the cap, afterall the cap does regulate the pressure in the system.
If not then i'd be running a pressure test on the system.

the header tank is definitely full and it didnt loose any coolant when i had it running.
if a stock cap fits on my pwr header tank ill grab a new one in the next few days and see how that goes.

gidday mate, did you bleed it with the cap off?