checked hoses etc. Am going to remove firewall panel soon to see if i can see anything. How does a pressure test actualy work, this is my guess they pump it up to a pressure higher than operating pressure and then look for the leaks? and will a pressure test detect a leak in the heater core or is it only when the heater is turned on that coolant flows through the heater core?
pressure test is done by introducing about 15psi into the cooling system over a period of 5-10mikes. the 15psi in the system usually will expose exactly where the leaks are. In bimmers, if the system cannot hold pressure, then the car will overheat. Pressure test will detect leaks in the heater core if your ignition is ON or car is running while doing the test.
*wet patch on floor could come from A/c condensate when the condensate discharge hose is clogged or disconnected.
** other test... turn on heater(KOER)and the whole cabin will smell of coolant if heater core is leaking-FOR SURE!
If you use green coolant. check spark plug condition. If you have a cylinder head leak(depending on severity) spark plug will be coolant wet, or have an orange hue at the electrodes(the effect of coolant burning in the combustion chambers)
Best of Luck to you
