Watch Those PCV Valves Kids
 

Yesterday morning I started my car and the engine was rough for maybe 10 or 20 seconds and the ECU light was flashing, then it smoothed out. Took it straight to the dealer and held my breath while they kept it overnight.

This morning I found out my PCV valve had failed and oil was flowing into the engine through the manifold, causing a recorded misfire on two cylinders and visible oil on the pistons of one of those and one other that had not yet recorded a misfire.

They replaced the PCV valve and tube and told me Audi now has a new design for these and is replacing them with the new ones but only on failed units, and ran engine cleaner through the car, though I'm dubious about how well this stuff works - hopefully not too much oil was in there and the failure was sudden and total rather than leaking oil in over time.

Given the opportunity, for others out there, I would replace them promptly even on cars not showing problems 'cause god knows how long it could be putting oil in your cylinders, building carbon in the valves, etc. before you start misfiring and end up in the shop.

Thanks for the notice.

If a failed Positive crankcase ventilation unit is really "pouring" oil into the intake manifold, then you have way more serious problems such as weak piston rings that can't take the built up crank case pressure caused when a PVC stays closed. Hmmm_ if it is a FSI engine, the intake manifold sees only_ air, and thus fuel never hits the top side of intake valves to clean the recycled EGR crap they force the engine to breathe. If your state does not have yearly EPA crap testing, an EGR block off plate cleans up that issue :) but will likely trigger environmental radicals to hunt you down.

I'm thinking the fact that these were characterized as failing in nontrivial numbers to the point that Audi designed a new replacement part makes my case non-unique, as opposed to bad rings or some other horrible problem. I mean, I certainly hope they would have mentioned it at the shop if this was an indicator of failed rings!