PCV Valve Breather Box on a 1998 Volvo S70 repair? Smoke coming thought the hosing!

First there is a small vacuum hose coming off the top of the engine that comes from that box to one of the larger tubes to the rear of the valve cover - remove it and make sure there is vacuum there if not the hose is cracked or blocked. IF the engine is creating too much vapor for the pcv system to handle you may have broken rings in the engine.Pull plugs and do a wet and dry engine compression test.