Water missing from the radiator :(

I used to get the "check coolent level " msg about once a week (after travelling about 150KM - 200KM) and when i checked the water in the radiator it was indeed low and would need to top up about 2 liters.
The mechanic has recently changed the radiator after finding a small leak at the lower part. But since then its got worst! now i need to top up every day...putting a preasure gauge does not show a change in preasure (maybe we need to keep it on for longer than half an hour) but i have just noticed some water dripping from the bottom of the passenger side of the car..not much just a slow drip but enough to make a decent puddle after a few hours..dont know if the water drip is from the ACond or is related to the leak...does any of this make sence? any advice is appreciated ..i fear the mechanic is going to change bit by bit before he finds the fault? The car is a BMWE39 , 5speed automatic 2003 520i - 2.2 L M54 thanks
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Look at the drip. Put it on your finger. If it is green and sticky, it is coolant. If it is not coolant, don't worry. If it it coolant, pop the hood and stick your head in and see where it is coming from. if it's coming from the overflow line, change the radiator cap. If it is coming from someplace else, change that. --scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

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Some water condensation from the A/C is normal, but that wouldn't account for the loss of coolant you continue to experience. The E39 radiator is a weakness (the first point of failure is usually the plastic hose-coupling areas), but you've changed that. I'd check all the fittings disconnected and reconnected in the R&R of the radiator first.
Check the plastic overflow tank for leaks. Check the radiator drain and bleed valves for integrity (O-rings can break/fail). Next check the water pump and the plastic thermostat housing. Check all hose connections and hoses. If the car has overheated (it doesn't take long in the red zone of the gauge), you may have warped/cracked the head or compromised the head gasket. This will allow coolant to flow where it doesn't belong. Typical manifestations are water vapor in the exhaust (particularly on start up), oily coolant and/or a light brown sludge in the oil (looks like chocolate milk shake residue on the dip stick).
There's been a problem with one of the aftermarket suppliers for the E39 radiator (can't remember which is the culprit, there are two commonly available) in which a small percentage of radiators fail VERY early after replacement. The cure is an all-aluminum radiator from Zionsville, but its about 2 1/2 times the cost of the OEM radiator.
R / John
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