have a bmw 328i, about 7 years old and approx 200,000 miles on the clock, have noticed that the coolant keeps droping in radiator, right down to bottom, and on a short journey, it can fill up again when i have drove for 30 mins, but most of time it just looses coolant over engine. it seems that it is leaking out of the engine somewhere under the injectors . but is it very hard to see. i pulled out the out the oil dip stip with engine running and there is a very noisy gurgling sound that is not normal. there does not seem to be oil in the radiator or water in the oil could this be a head gasket problem?