Eric..
Plastic necks in these radiators are weak indeed. The 528i along with your 540 seems to share the same weak point regardless of the length/shape of the upper hose. That T coupled with an extra connector has something to do with alternator cooling on some newer models. Once a flexible rubbery hose is cut in length and connected to rigid material (in this case the extra connector) it becomes less flexible; thus more stress on an already weak radiator point; that is the plastic neck of the radiator.
Mine broke twice: Once when a very fat mechanic (he is my friend don't laugh)leaned on it with his left hand while checking some vacuum hoses for a leak--shame on him. The second time when my engine got flooded; I went on to pull the hose off the neck with the clamp loose when the neck came off stuffed in the lumen of the upper hose-- shame on me.
In sum: An upgraded metal type of radiator and/or neck makes more sense; at least when it breaks I can sharpen my skills in welding/soldering and save $200 each time it breaks--Well for this one? Shame on them.
Notes for further reflections: The point about the vibration traveling from the high/low revs of the engine to the neck via the upper radiator hose sounds interesting so I like to add the following "untested remarks" for further discussions:
A. How much of this apparent engine force/stress/vibration/torque if you wish, find it way to the neck via flexible 2 hoses? Is there any?
B. I believe a shorter 2 hoses with a rigid middle connector will be more faithful in transferring much larger shocks, if there are any to begin with, to the neck than a single long flexible hose. Yes? No?
used
C. When the engine mounts (save the tranny’s for now) are new/relatively new; they do their job of absorbing these repetitive/constant shocks to the neck. Once the car gets older (running rough/unstable idling/ weaker mounts etc) the neck simply gives up. Is this a far fetched argument? Or
D. Don’t forget the larger effect of the tremendous heat generated by both: the coolant (traveling inside the neck) and the engine’s on the outside—for sure there is no mercy there especially around summer times.
regards
billb
