Losing Radiator Coolant

[drdchin]

I have a 1997 e39 with 125,000 miles. About 2 months ago I noticed that I was a little low on coolant. I refilled it, but now it seems that I'm losing more fluid. I checked the radiator, hoses, water pump and no leak. The car runs great, temperature gauge is normal, no over heating. Under the car, I found coolant leaking from the front of the engine block, right below the vibration damper. Any thoughts on where this leak is? Also, what is everybody's thought on bottled sealants, like Bars or K Seal, to fix coolant leaks?

[westin]

got the same car same problem im about pressure test it ,its seems tovery slow but its there.I suggest you do the same ,the water pump and thermostat housing are in that area.Im pretty sure autozone has a tester that might work.

[Lord Vader]

Double check the water pump. The seals can fail causing a leak. If its from the front of the engine block it could also be the thermostat housing has cracked (if you still have the original plastic one. Bars Leak or those other sealant products wont fix a crack in the plastic.

[bpde328i]

Just experienced similar problem on my 2000 328i. Coolant leak originating from radiator, after 178K. Going to replace radiator, water pump,thermostat, upper and lower hoses, clamps, coolant, etc. Bav Auto has a kit with all components for $390 shipped. This will be the first radiator / pump replacement in 13 years.

[drdchin]

You guys were right, it was the water pump. I couldn't see the slow leak until I took the fan and belts off. Changed the water pump yesterday and drove fine today. The job took me about 3 hours. Thanks. These forums are great.