Volvos and a few other EURO cars are DIFFERENT in that they do NOT have a typical PCV valve to rid the engine of VAPORS and CONDENSTAION! They have a FLAME TRAP< wwhcih is more complex but more refined. On ALL Volvo engines, it MUST be replaced every 100k miles, and resides UNDER the intake manifold. Thee replacement is about $50 or so and WROTH the money. CHANCES are that your engine was weaned on VAVLOLINE like most car engines have been. If so, I guarantee you will have LOTS of coating and sludge on engien parts, including teh engien RINGS! This is NOT really so bad, since it is EASAY to remove and restore to ORIGINAL SHOROOM condtions with a little effort. Your VOLVO TURBO engine is VIRTUALLY idestructible, except for it's vulnerability to POOR oil choices that will DESTROTY the turbo bearings and also clog up INTAKS and jamb up piston rings. >YOU NEED A DE SLDUGING TREATMENT>>>> First buy that new FALME TRAP and install it by removing the intake manfiold, It is an EASY job and STRAGHT FORWARD and fool proof. It does NOT involve the COOLING SYSTEM GAKSET in any way at all. REMOVE And REPLACE the FLAME TRAP (oil seperator). REMOVE the VALVE COVER and take i to a reliable machine shop where they can fully STEAM CLEAN all the junk from the back of it and the air passageways. While this is being done, use the AMsOIL FOAMING cleaner to easily remove the JUNK built up on the visible portions of the CYLINDER HEAD! it will harm NOTHING! THE OLD SLUDGE WILL easily DISSOLVE AND SLIDE AWAY, iT WILL GET PICKED UP BY THE oil filter WHEN ENGINE IS STARTED UP. dO not CHANGE THE OIL until YOU HAVE USED A PROPER SASLUDGE REMOVING AGENT, LIKE lubro-moly- OR amsoil CRANKCASE CLEANER. b-g MAKES ONE, THAT IS NOT AS POWERFUL BUT AN okay START. eVENTAULLY YOU WILL restore THIS THING TO brand new CONDITIONS. uSE only OIL WITH A volvo RECOMMENDATION SPEC NUMBER, LIKE mobil one 0w-40, pentosin, THE FACTORY OIL, or TOTAL from France or LUBRO-MOLY. THE GOOEY VAPORS and STEAM indicate that your rings are clogged up a bit or that the FOLQAME TRAP is totaly clogged up. NOT BIG PROBELMS!!! ON EURO cars, I use the AMSOIL FAOMER to inejct into vacant plug holes. It will SETTLE on the rings and dissolve the sludge and varnisha dn more ollectd over the years, and restore to NEW condition. The VOLVO BLOCKS will not even have wear in them yet! Allowing the AMSOIL FOMER to circulate thrrough your TURBO oil feed and return lines will remove the PLAQUE clogging them up, and add YEARS of life to the turbo charger. Luckily, you can even remvoe tehse PIPES for cleaning or replacing if they are REALLY CLOGGEED UP< like bad arteries are). If you have ANY more questions about this, feel free to contactme anytime. I accept donations for my expertise as well. You will save THOUSANDS of doallars over tim by perorming the tasks I list heere. FUEL mileae will improve, adn engine parts will last even LONGER!!!