I smelled coolant last night when I was going through the drive-in ATM so I quickly pulled over, while engine was running, opened the hood and did not see any wet coolant or leaks near the hoses or at the base of the radiator. When I got home however, I noticed a small trail of coolant on the driveway. From the position of the spill, it looks like it was dripping right under the drivers side front seat. I looked underneath and sure enough, the car was wet with coolant at about that location. I will investigate further, after work today when I have the proper light and tools but can anyone speculate on where the leak might be originating? 1995 525i http://www.realoem.com/bmw/showparts.do?model=HD63&mospid=47404&btnr=11_1123&hg=11&fg=35 Thanks
Sure we can speculate but it really won't do you much good. You need to go ahead and inspect your car and determine exactly where the leak is.
I'd suspect the expansion tank, but you need to get under it and see if it's cracked & leaking - could be a number of items on that side of the radiator. http://www.realoem.com/bmw/showparts.do?model=HD63&mospid=47404&btnr=17_0099&hg=17&fg=05
If it isn't blowing back and is actually leaking from the vicinity of your driver's seat, I'd say it is your heater core.
Found the souce of the leak Looks like the auxiliary water pump is leaking - All the hoses leading in and out of the pump are fine but when I looked at the aux water pump with a dental mirror, I saw the leak coming right out of the aux water pump, on the bottom of the pump
I found a Hella auxiliary water pump for $125.00 at USAAutoparts.net. Pelican Parts wanted $163.00 for the same part. -Tom
I don't know how DIY-ambitious you are, but if the pump still works fine and just has a leaky housing, it may be re-sealable (possibly an o-ring). Also, just as a caution, sometimes leaks can be deceiving. I spent days chasing down a coolant leak on my old 530i that ended up being a hairline fracture in the thermostat housing. Gravity makes it hard to find the source Not questioning your diagnosis, just throwing in my .02
Coolant Leak Fixed Turns out that the aux. water pump was leaking from a seal. I replaced it - all better now. You can sort of see from the photo, that the coolant was escaping from a bad seal. Thanks to everyone for the input.
