I got my first dream machine - 2001 540iA M-pkg 3 months ago with 180kms. Previous owner apparently replaced WP, fan clutch and belts/tensioners in May this year (I believe he did) and car is overall in great shape. Here's what's happening: I see no obvious coolant leaks, after 10 min of engine running, temp goes past the middle mark, top radiator hose is warm but bottom one (coming out of the radiator) is dead cold and I have no warm air in the cabin no matter what temp I set in the cabin. Is this the thermostat issue or the WP? How do I tell?