Don't know anything about that stuff,but sounds like you have a few other little problems though.
If you have an m54 engine full coolant overhaul is required if one of the components fail the rest are not far behind.
Oil leaking could be the, oilfilter housing ,valve cover gasket, or ccv related.
Water more than likely is the rad or the expansion bottle split, or any of the pipes big and small in the system .
Possible the reason you have no heat is coolant level gone too low and you have an airlock in the cabin heater portion of the coolant system.
Your thermostat may well be stuffed but given the fact you are loosing coolant and oil. Identify the cause these issues first then see what your left with.
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