What could be blocked that i haven't checked in 230F engine? I have determined hoses, flame trap, box below intake manifold, orifice on same manifold are clear but oil filler cap still rattles when loose, is this an indication that something is blocked? Local guru says the cap should hold steady at an idle.....thanks for reply!!!

 

replace gasket on cap

 

If you are building up alot of pressure it might be something in the engine.

 

I'm having a similar problem... Leakage from the front valve (right on to my derned exhaust... Smoky!) I checked the flame trap and hoses associated with the flame trap. All OK. How do I check the box BELOW the flame trap? It's kinda hard to get to... Any other suggestions?

 

You can blow compressed air into it or a hose form it. Or even the dipstick and see if it comes out the oil filler cap.

Also have you changed the gasket lately? If so you might also have a warped Valve cover.