Blow by, small amount of exhaust smoke

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New Member
Aug 27, 2022
W204 C220CDI
Hi guys,
So I had my injector seals changed recently as had the black death, mechanic messed the whole job up ended up doing it myself, car runs alot better now, brand new injectors, new seals, had to use a thicker copper washer to get a good seal, he had the rocker cover gasket off, used silicone to put it back together, when I recieved the car back it was puffing ALOT of black smoke, I seem to have sorted that by cutting the seats for the injectors, now since getting the car back, I have alot of blowby coming from the oil cap. Small amount of smoke on start up then seems okay, power is okay, engine seems to run a little different since getting back from soppy bollocks and me rectifying injectors but, ticks over fine, boosts fine, the blow by is excessive though, the engine gets very hot and crankcase vent is leaking smoke, coolant sits at 90 which seems fine though, i dont know if it's a really worrying sign, or whether i can just drive the car as normal and wait to see what plays out, when the guy attempted to replace seals he muddled up the order of the injectors, then tried starting it up, ran it, revved it, drove it, engine was not happy at all hence the new injectors, I didn't end up paying the guy for obvious reasons, the crankcase vent is part of the rocker cover built on so, could the blowby be from the rocker gasket being put on wrong? Or does this sound like a more serious problem? The engine is on 148,000, seemed to run better before he touched it to be honest, love the car, really want to fix it but need to know how much it will cost to fix. I feel like mabye the valve/stem seals could be the cause as there is hardly any exhaust smoke at all really, or I also think mabye, the amount of black smoke cause by the faulty mechanic could have blocked something like a vacuum or something I'm not too sure I dont know alot just what I've learned online. I was getting a high pressure fuel engine code p0088 but since putting in the I injectors it's gone away for now, it may come back, I've read the QCV valve could be the problem and cause smoke in vent issues, and poor idle, high presure fuel code, anyone else have these issues and fixed it? 0m646 engine
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