Thread: Coolant not circulating

Hi Epic , have you tried bleeding the system again ? what makes you say it's not circulating , sometimes the telltale gets blocked. Any coolant stains ?

I guess that I would suspect the thermostat first.
Also check that the hoses are on it the correct way,although if it just started out of the blue this is probably ruled out.

Regards Philip A

Hi, when you say the gauge started to move, do you mean up from the middle or up - down and it's rpm dependent?...describe better the symptom cos it's important

I havent tried to bleed system yet. Will be tomorrow incase its an air blockage. But system has been fine and closed for a year. Coolant levels do not drop. The temp Guage moves from normal central spot and starts going up. There is no water in the expansion tank when it happens. Its like water isnt flowing back into it. Then soon as loosen radiator cap, pressure is released and water levels return to normal. Hoses are not hard or over pressurized. Hoses are on thermostat correct way round, had no trouble at all for ages lol. Temp Guage doesnt seem to be rpm dependant. It is once vehicle is up to temp runs as normal till its warm other than seemed to warm up slower than normal but that might just be me imagining that.

Is the radiator hot top and bottom?
If hot = Fan or airflow
If cool at the bottom = thermostat or pump flow

with cold engine remove the bleed screw, ask somebody to start it and give it a short throttle to rev it above 1500rpm, if the pump works the coolant should gush out up toward the bonnet with good pressure, if not the pump doesnt work if it passes this test try to stop the viscous fan with a rolled newspaper when the radiator is hot, if you can it means it dosnt lock, it's just freewheeling and there's no air flow to cool the rad.

check that the small return line from the top of the radiator is not blocked you should be able to see coolant flowing from it into the reservoir with the cap off

head gasket pressurising system.