HEAT, AGE AND PLASTIC
– no, not a stroll along Hollywood Boulevard, but a brittle mix of failing parts under the bonnet of my BMW (Bloody More Work!).
Having made contact with a couple of previous owners, I knew some of the older pipes had been changed, which is confirmed by the date stamps on the more accessible bits. I also knew that the crankcase ventilation system (CCV, for ‘crankcase vent valve’), which consists of several hoses and an oil separator, was still on the to-do list.
I’d previously noticed a puff or two of white smoke from the exhaust but hoped that the service I’d done would have cured all of that nonsense. It didn’t. A bit of Googling suggested that smoke can be a symptom of a failing CCV system, along with a small whine (which I have been hearing for some time now) and white deposits under the oil cap. The CCV system takes air from within the engine and sends it to the oil separator, which returns liquid oil back to the sump via the dipstick tube and diverts the oil vapour to the intake manifold for combustion. Sounds clever, but in reality it’s an over-complicated, poorly designed weak point in an incredibly inaccessible place.
Cold climates and short runs create condensation in the unit, which doesn’t get a chance to burn off and creates a thick, creamy gunk. Worst case is that it blocks the pipes and sucks the sump dry of oil and throws it into the air intake, causing hydrolock. Sounds cool, but apparently it’s very bad. The solution? Wrap everything in chunky insulation to heat the oil quicker.
Without taking the whole of the intake manifold off, removing the old hoses is a pain, but doable. Once I’ve removed the air filter, DISA (Differenzierte Sauganlage, or ‘intake manifold adjuster’) valve, throttle body, idle control valve and wiring harness, and unplugged about 20 cables, I can gain ‘access’. YouTube suggests breaking the hose clips and cutting the pipes for simplicity’s sake; I try to be non-destructive, but inevitably s
