chrisvlok 0 Report post Posted October 30, 2009 Hi all, was on the track today in my newly built e30 which was the first run up etc. got to about 4 laps when she blew the heater hose that goes to the header tank off and over heated. what caused it? we have modified the cooling system to work with a 325i radiator. the cooling out put on the drivers side goes to the nearest one on the radiator and obviousl the other one to the other port n radiator. then the heater hose port on header tank goes to the heater hose that would usualy be attached to the bottem of the m40's original radiator. and the breather hose to breather hose ofcourse. Is this a set up or disaster? has anybody done this before? it has just had a new water pump, thermostat etc. only things i can think of is wether or not my plumping is routed wrong. after this all happend, i re bled the system and tightend the section of heater hose that came off. idles fine but when i take it for a spin it blows the same hose off and same probems occur. Can it be that the pressure cap for the header tank is to heavy for my m40? (cap off a 320i) or blowen head gasket? not blowing smoke or any commen signs but it seems to be only culprit. please help thanks Quote Share this post Link to post Share on other sites