Hi, try changing expansion bottle cap. It regulates the pressure, had it once to fail. Worse case scenario could be cylinder head, or gasket etc. Hope it helps.

 

Maybe water pump too.

 

Depending on the extent, this could be normal. The hoses and expansion tank are supposed to be under pressure, it stops the coolant from boiling. The cap will have a set release pressure, which when reached will dump fluid from an over flow tube.

Dont jump to conclusions and panic before investigating properly.

Be careful when undoing the cap, the sudden release of pressure can cause the fluid to rapidly boil and expand out of the chamber scalding you.

Pat.

 

Hi I appreciate this is a long shot but did you get to the bottom of this issue? I have a 2010 Cr35 with the same issues, I did step by step try all the small cheaper parts first thermostat, expansion tank, lower rad hose, radiator and ended up having a new head once I stripped it as the original failed a pressure test on the first attempt but passed on the second attempt. Not trusting this and with the van been my own service van I didn’t want to waste time and effort so to be safe went for a brand new head. When I first started it there seemed to be a air lock so I put a bit bottle of coolant on the expansion tank and filled to higher than the system left over night, the level went down and when pressing the pipes no more bubbles just water movement as expected. The only thing I’m worried about is it seems to have excess pressure in the coolant pipes and stays under pressure. It seems less after doing the high water over night but still appears to have excessive pressure in pipes??
sorry for the long post any help wouldbeappreciated thank you.