I have an E36, 1998, 328i. Sometime after 108,000 miles I noticed a slight coolant loss. Amount of loss seems dependant on mileage driven between checks, not ambient temperatures.
I have recently replaced the coolant cap. And I have checked the hoses. There does not appear to be a visible leak; no puddles on the floor.
Earlier in 2006 the thermostat and related gaskets were replaced. The engine warms up as it should and never overheats.
I noticed micro stress cracks in the coolant overflow reservoir. Seem like they have been there a while, but maybe not forever.
There was a mention in this NG recently about the reservoir cracking and leaking.
Any help? TIA!