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I'm doing some trouble shooting and have taken off my upper plenum. Saw all this oil caked on the runners and needed some insight on if this is excessive or normal. I have PCV breathers on so no need for a catch can, but that's only been on in the last 10k miles (72k miles of no catch can and pcv routed through intakes). The oil pattern doesn't look like cylinder blow by but I could be wrong as I'm no expert. The oil is primarily caked on the outside curvature walls where the runners redirect the flow, indicating the oil was in the airflow and the momentum of the oil particulate carried it to the wall when changing direction (Runners photographed 1-6 l, front to back, on both lower and upper).
I also found oil pooled in the middle drivers side spark plug hole.
Here's a couple pics of my 2003 100k mile DE. Not sure if you've got an oil issue but possibly a reversion issue or a "direct port sucks" issue? I run a baffled catch can which does not catch 100% of the oil btw. I think breathers might be "an" issue, potentially one of 2 or more issues because they do not draw air from the crank case, they just "let it breath". I believe it's a good thing for some oil to get into the combustion chamber top side to help lube the rings due to tight tolerances, not just to recirculate for emissions control.
You're valves are coated and perhaps the runners are as well, in the way way and due to the same issues, direct port injection being one.
Last edited by onevq35de; Nov 30, 2018 at 07:46 PM.