Positive crankcase pressure in Astra H 2008 Z14XEP

Question

I've been suspecting an issue with the PCV system in my Opel Astra H 2008 with a Z14XEP petrol engine. It blew both the oil pressure switch and (probably, have yet to investigate) the front crankcase seal in short succession.

I tried the old "balloon on the oil dipstick tube" trick, which seems to show significant positive pressure inside the crankcase, even at idle.

Video: https://drive.google.com/file/d/0B19XZxlznCy5WXdXMUhtaFNUNjQ/view?usp=sharing

The video was taken at idle. I think I can feel individual cilinder pulses in the balloon.

How do I fix this issue? I checked the rather large hose going from the valve cover to the T junction before the throttle body and it's not blocked.

Some additional information: the engine oil cap is always caked with a mayonnaise like substance. This is apparently rather common on these engines and not indicative of head gasket failure. The engine oil does not contain coolant.

Do I need to install a new valve cover?

Edit: I found some related material: here. It's not the exact engine (1.6L instead of 1.4L) but it's close. I checked the hose that connects to the intake manifold and that's definitely not blocked (lot's of vacuum).

Answer 1

Sound to me like I would want to rule out a cylinder head gasket, or possibly a cylinder head.

You could have a leak from the coolant to the oil passage, which is causing coolant to mix with oil, giving you the baby poop look inside the cap.

Also, if you have a combustion to oil leakage that could cause the seal to go. The oil pressure switch doesn't make sense just yet, as it should handle rather high pressures, UNLESS your combustion is flowing into your oil at higher power levels.

What does your coolant overflow bottle look like? If it is contaminated, that is one more check mark towards a cylinder head pull.

You need to be really careful. If the gasket has gone, you may not be cooling and lubricating your cylinder head properly and it could have a catastrophic failure. Also your radiator and cabin heater could blow if they get overpressured and your radiator cap has insufficient capacity to vent combustion leakage.

I urge you to resolve this before you put more miles on the engine, and potentially do more serious damage.

Cost wise, look for 1. mixing of fluids, 2. contamination of coolant with exhaust byproducts, 3. compression test which can be done with a relatively low cost gauge.