Originally Posted by McDonaldD

Sure, if you're in there, why not? But what I don't get: The smoke comes out of the exhaust pipes, no? Why not replace your headers, cats, oxygen sensors, mufflers and exhaust pipes? Oh, don't forget the chrome tips; there's a tool for that, too, no? I'm sorry for being a jerk but one may purchase any number of tools to replace any number of parts. People are attempting to repair their cars. They're not dabling in buying tools or replacing parts for replacement's sake. If you're replacing for replacement's sake, why not Start afresh? Buy the new F15 and move on?

I, too, fell prey to the "while you're at it" crowd. I replaced the coolant transfer pipe while replacing my upper engine seals. There was a useless tool for that as well...but thats another tale about why one should understand a part's potential for failure BEFORE assuming failure could, in any way, exhibit symptoms stated as the reason for said part's replacement. On the e53's N62? no. On previous versions, possibly? Anyway.

My comments about the valve stem seal fallacy narrowly apply to an engine that meets ALL of the following criteria:
- at operating temperature
- after a period of prolonged idle
- puffs/clouds of bluish smoke envelope the world behind you as you accelerate from the aforementioned state of prolonged idle.

My comments do not broadly apply to any of following:
- Pure white whisps, puffs, clouds of smoke - Congrats to the >99% that have found the dew point. My condolences to the unlucky <1% that have coolant making its way into their combustion chamber (and, likely, oil)
- bluish puff or cloud on startup - you have found the fabled valve stem seal issue. The automotive world and modern science would like to know, please, how you managed to torture your vehicle into such a sad state of disrepair. Please join the <1% in the coolant club as you have likely severly overheated your engine.

If your vehicle falls into the narrowly defined yet widespread blue-cloud-off-of-idle problem, continue reading.



The valve stem seals do not contribute to the failure of the crank case ventilation system in the way you think they do. The seals expand with heat, not contract. This means, while hot, the seals are larger than they are while cold. After the engine cools, the valve stem seals shrink, allowing oil/air to slip past. If the valve stem seal were to fail, it would fail first while cold. Sure, a puff of blue smoke on startup may go unnoticed. Say you never notice the puffs of smoke on startup and the valve stem seal failure progresses to a point where they fail to seal even while warm/hot; they're just always leaking. This, you have asserted, is the point of failure that would cause crankcase ventilation failure. BUT it does not make the previous symptoms go away. It would smoke from oil leaking down into the cylinders AND from such a state of catastrophic failure that this new blowby path overcomes the vacuum in the crankcase. It would smoke on cold startup and hot startup. It would just smoke. ALWAYS. Yet this is not the case. The issue I, and countless others, have experienced only smokes at a very particular time: a cloud of bluish smoke after prolonged idle at operating temperatures.

My point is, valve stem seals cannot fail in the way you, A B Able, have stated without also exhibting the other symptoms. No oil-cloud on startup, no failed valve stem seal.



You should never have oil, film or otherwise, in your intake manifold. The intake manifold should be pristinely dry and free of ANY residue. Oil in your intake can only come from the PRVs/crankcase ventilation system failure. This is the failure that causes oil consumption.



If you meant your intake manifold was clean, disregard the rest of this: Your throttle body will likely always be clean. The intake manifold, behind it, will be coated with oil. You'd have to push on the top of the throttle plate and then peer in with a flashlight. My intake manifold's plastic was supposed to be green but instead it looked black. You likely will not see pools of oil as the intake is quite deep. The reason the throttle body is clean while the intake manifold is smothered in oil is because the crankcase ventilation system bypasses the throttle body. The vents connect directly to the intake manifold: Above and below the throttle body.