How to change PCV valve in B18C4 MB6? in Engine Posted March 12 I tried to change the original PCV valve with a new aftermarket one (cheap). It was hard to remove the old one and it cracked in two pieces. I got it all out eventually while very frustrating. Putting the new one was surprisingly hard too. I did attach it to the hose surprisingly easily but it was hard to press the new valve back into the hole. There's no space so hard to apply any strengh. I'm not sure if it's all the way down. It looks pretty good but i think it could be a little off. The aftermarket valves rubber part was a bit longer than in the old OEM one. Maybe that makes it hard too. Anyway tried to start the car after all the work and i think the idling is a bit off. It could be running lean or rich if i installed it wrong... There is some smell and exhaust gas smells a bit rich too although i always had trouble with emissions/car running too rich. Also the car is using oil so that's also the reason for trying to change pcv valve. I haven't test driven yet but i'm afraid i could've made things worse. Might have to take the car to a car mechanic. Tried to save some money by doing it myself because the valve is in a bad spot in these engines as you may know. Is it harmful to the engine if i installed it badly? Is running rich or lean harmful to engine? When i pressed the gas pedal at idle it didnt sound healthy/strong. Choking sounds and hesitating sound but the pedal feel was normal. Should i try to drive the car or let someone take a look?