Excess crank pressure
 

My 2007 D5 consumes oil alarmingly. No oil leaks whatsoever. Taking off the oil filler cap on tick over is like opening a shaken bottle of coke! Same if pull out the dip stick too. Have been getting blocked DPF and am told by dpf guy that this is the route cause of the problem, excess crank breathing pressure forcing oil into induction system, causing vehicle to smoke and choking up DPF.

So what can cause the pressure?

Excess crankcase pressure can be caused by a blown head gasket, leaking valve seals or worn piston rings - amongst other things. These will also account for the oil consumption.

Well before a full top end strip down I’d like to start with basics!! I put a rubber glove over the oil filler and started it up and it blew up like a bloody great balloon!! Is it possible that the brake vacuum pump could leak internally into the rocker cover? I’ve been checking various vacuum pipes and have found nothing of note yet.

On a running engine, you can check the vacuum pump directly with a tester with the brake booster attached and again with the brake booster connector removed but the brake booster hole on the vacuum pump securely blocked off.

If the result is the same steady, full vacuum, the booster vacuum seals are fine.

I’ve just changed the crank case breather valve, part no 8642424, transformed the breathing and pressure. I guess this had caused excess pressure that resulted in oil being forced into the combustion process and causing issues with the DPF filter. Now to clean that!

Hi, could you tell me where on the engine the breather is that you changed? Photo even better! thanks.

Please tell us the mileage and engine type - assume its 180k + ona 185bhp?