The engine in my Volvo keeps spitting out the small round lid on the end of the cylinderhead (just at the end of the camshaft). I changed it yesterday, and now it is gone again. Should I use treadlock when mounting it? Or maybe there is a reason why there is pressure in the cylinderhead? Could the breather, if clogged, be affecting this maybe? Any help is appreciated.

 

My xc70 has a not so good pvc system . I had 1 of my cam seals blow out and spray oil all over.
The seal had a loose press fit more like a slip fit, so i put some gasket glue on it and pressed it back in. Now i just leave my dipstick out a little to vent till I clean my pvc system.
its worked fine for 6 or 7 months so far.

 

yes, a clogged oil separator box and flame trap causes these engines to blow seals and such.

the B230 engines don't have a conventional "PCV valve", instead, there's an 'oil seperator box' on the left (intake) side of the block, under the intake manifold, and a breather tube comes off the top of this, in the breather tube is a 'flame trap' which is just a little disk of hard plastic or something that has a bunch of pinholes in it (turbos don't have these), then the hose connects to the intake manifold. when your engine gets older, and there's more 'blowby', the crankcase fumes get nastier, and they condense in this separator box and clog it up. ideally, you clean the 'flame trap' every oil change, but most people don't. when its really fouled up, its easier to just replace. every so often, you really should remove the oil separator box, and wash it out with a strong degreaser, then rinse it clean and dry it before reinstalling. inspect all the tubing involved, replace any thats cracked or hardened.

if you have an EGR, the separator box is a SOB to get it, about the only way is to unbolt the intake manifold and swing it back away from the engine, replacing the manifold gasket when you put it back.

leaving the dipstick out is a terrible idea... excess crankcase pressure can blow significant quantities of oil out that tube, all over the engine.

 

That is exelent advice Pierce! Thank you! Also, good idea to get hold of a new intake-manifold-gasket before attempting to clean the said flame-trap.

 

No disrespect pierce you know these volvo engines way better than I.
I have a xc70 with the I5 and low pressure turbo, that's the only volvo engine i know anything about.
leaving the dipstick out a tad doesn't leek oil or spray mist into the engine compartment, like i said i have been doing this for 6 months no oil
, but it is just a bandaid to keep pressure down till fixed !

 

the dipstick tube goes below the oil level, so if there's enough positive pressure in the crankcase, it WILL blow oil out, this is true for most cars. now, it takes a few PSI to lift enough oil up to the top of the tube.