318ti.org forum - View Single Post - Mysterious M44 Coolant Leak

Boston_Green_m42ti · 11-27-2018, 01:46 AM

Hi all,

I've noticed a puddle of coolant under the AC compressor on my 1998 318ti (203k miles) in the last few weeks. I bought the car last May, and had no cooling issues until this - perhaps not coincidently we had our first cold front move through around the time the leak started (overnight lows in the mid-teens).

I've tightened the hoses on the T-stat and have cleaned the front of the upper timing case to check if this is where the leak is coming from. I don't see any evidence that the leak is from the T-stat housing or the hoses.

The leak appears to be coming from near the mating surface of the upper and lower timing case covers just below the timing chain tensioner. There is visible coolant coming down both sides of the compressor. Does the m44 have a profile gasket that could leak coolant in this area? Any other thoughts as to what may be happening?

I've driven the car about 70 miles since this has happened and have not noticed any white smoke or mixing of oil and coolant.

Any thoughts appreciated. Thanks!

11-27-2018, 01:46 AM	#1
Boston_Green_m42ti Junior Member Join Date: Feb 2015 Location: Albuquerque, NM Posts: 7 iTrader: (0) Photo Gallery	Mysterious M44 Coolant Leak - Please Help! Hi all, I've noticed a puddle of coolant under the AC compressor on my 1998 318ti (203k miles) in the last few weeks. I bought the car last May, and had no cooling issues until this - perhaps not coincidently we had our first cold front move through around the time the leak started (overnight lows in the mid-teens). I've tightened the hoses on the T-stat and have cleaned the front of the upper timing case to check if this is where the leak is coming from. I don't see any evidence that the leak is from the T-stat housing or the hoses. The leak appears to be coming from near the mating surface of the upper and lower timing case covers just below the timing chain tensioner. There is visible coolant coming down both sides of the compressor. Does the m44 have a profile gasket that could leak coolant in this area? Any other thoughts as to what may be happening? I've driven the car about 70 miles since this has happened and have not noticed any white smoke or mixing of oil and coolant. Any thoughts appreciated. Thanks!