Hey all,

2009 B2300, 190k km on the clock. I am the original owner of the vehicle.

I noticed a bit of a stumble at wide open throttle so I started poking around. After some troubleshooting, I noticed some pressure coming out of the spark plug wells on the top of the valve cover. This pressure is strong enough that it’s pushing the #2 spark plug boot off the plug.

I’ve noticed light oil seepage around my valve cover gasket for some time, but had been putting it off because it’s such a PITA to do. Same for the PCV; dealership couldn’t give me a service interval on it so I just let it be. Neither have been touched since the truck left the factory.

So, my plan is as follows:
Tear off that stupid intake and do the PCV and valve cover gasket at the same time. Button it all up and make sure everything works, then likely throw a new coil on it. Plugs and wires are overdue anyway, so I’ll throw some on there too.

It’s not throwing any CELs, which I think is weird because it’s got a completely dead cylinder when the boot pops off. Is this not something the PCM should pick up on?

Anything else I should be worried about? Does it seem like I’m on the right track? How much crankcase pressure is normal?

My big nightmare is that the rings or valve seals are pooched and creating pressure in the valve cover, but the truck is low mileage, doesn’t smoke at all, and has always had regular oil changes. I also don’t really have the tools to do a leak down test.

 

Compression test would indicate if the rings are a problem.

 

Turns out the plug worked itself loose and compression was bypassing the threads, causing the boot to blow off. Luckily, it wasn’t loose enough to chew up the threads in the head.

I guess the oil from the valve cover leak and a thousand or so heat cycles allowed the plug to back itself out.

A new set of plugs and she’s running strong, and I get a lesson in checking the simple stuff first.