I assume this is in a turbo car? Your pcv valve may be stuck and allowed positive pressure to build in your head, the cap may have already been poorly sealed, or if it's original it may have been fatiqued. Blow by could be another more serious issue but check the pcv valve first, to check it remove it from the car and give it a gentle shake, if it doesn't rattle it is stuck! If nto blow through both ends and the valve should shut and not leak significantly.

Also the cap is replaced with a bit of rtv when you do, I would recommend a new cap as well

 

yes turbo car, the PCV valve is not stuck, i had head work done about 3 years ago. what would be the more serious issue ?

 

It could possibly be a one off occurrence (ie it was poorly sealed into the head and fell out) though I wouldn't end the troubeshooting at that yet. A more serious occurrence again would be blow by, but you should get a popped dip stick and oil all over the front of your motor in that situation

 

okay
my dip stick was fine and no oil in the front of the motor
ill keep an eye open for it

 

DDG- Common failure items and mistakes

10) Rear cam plug falling out.

Well it's not so much falling out as loosing tension with age and blowby from a high mileage engine pushes it out. Next thing you know there is a cloud of oil behind you and several people have managed to drive their car long enough to loose all the oil in the engine and damage the motor! To prevent this from happening (or while re-installing) put a thin coat of Permatex Number 1 (Which is NOT RTV) around the seals perimeter when installing a new seal. You can use RTV but I don't recommend it. Permatex Number 1 doesn't quite dry and stays flexible so it grips the head better compared to RTV which while drying is a hell of a lubricant and when it does dry the engine oil slowly starts to seep it's way around it.

 

Mine did the same thing about 7-8 years ago.
Rear Cam plug fell out while driving to work.
Luckily I was only 1/2 mile away, lost almost 3 qts of oil.

Clean the area of all grease/oil with brake cleaner.
Apply Permatex Aviation Cement or Permatex #2(a non hardening sealer) to the outside of the new Cam Plug and install it in the head tapping it in lightly.
DO NOT use RTV, it is too slippery and the plug will come out again.

FEL-PRO #TCS45833
http://www.autozone.com/internal-engine/camshaft-oil-seal/felpro-camshaft-oil-seal/68196_0_0/

PERMATEX #2
Gasket Sealants : Permatex® Form-A-Gasket® No. 2 Sealant

 

Thanks NAJ your the man !
would locktite #2 be acceptable as a sealant ?
i have alot of that on hand

 

Good to know thanks guys for chiming in, apologies for the RTV suggestion... that is probably why they pop out for some people lol!

 

RTV will work fine if you let it cure at least 24 hours and make sure the parts are very clean and dry

 

If this is what you are referring I am "assuming" it is similar to Permatex #2.

https://www.carltonbates.com/static/catalog/products/images/PDF/LOCTITE_GS2-EN.pdf

 

Even the most efficient PCV system can get overrun by excessive blowby. In which case, I would rather this plug pop out rather than the rear main seal.

So, hopefully the plug was just old and loose.

 

Quick follow up that i forgot to post
i was inspecting my PCV valve when this happened and notcied that the PCV valve grommet was completely destroyed ( torn/split from the bottom down ) i have no idea how long it was like that but i have since replaced it

what would be the cause of this blowby ?

like I said i just had the compete engine done not even 10,000 miles ago
removed the head and had that redone with a sliding cam
removed the block and had that completely redone
i pretty much have a brand new engine so im concerned. I don't know if the cap used was old or fatigued and really have no way of knowing

 

Unless the PCV system is restricted and there is no place for the crankcase pressure to go I doubt you have a problem.
Chances are the cam cap was old and worn out and popped by itself and if you installed the new one properly you should have no problems.
Just keep an eye on it.

 

Since the engine work was completed have you run a compression test on each cylinder to determine if the rings have properly seated and the valves are working properly?

 

If the engine is running fine otherwise, I wouldn't worry about it. The cam caps just fall out over time. It's only held in by friction between the rubber coating and the hole surface. That's why people recommend a sealer to help secure it. This has happened to plenty of us over the years with no ill effect and nothing else "wrong" with the engine.