Hi!
So, as my son was sitting in his car in a driveway with idling engine, I heard the engine started to sound like a diesel. At the same time the codes P0026 and P0027 appeared. These codes are for the variable valve Train (VVT) intake and exhaust monitoring solenoids. The possibility of both going bad at the same time is literally ZERO. Also, the sound at idling really worried me, because it sounded like oil starvation. The sound seems to be coming from the area of the solenoids/timing belt. Camshaft seals and new timing belt were replaced 6 weeks ago. Other than the jumped timing and possibly BOTH solenoids going bad, what could it be? Does anybody know what else could it be? I've heard that a blocked oil passage/line could give these codes (and tapping?). UPDATE - further review of internet indicated that either the VVT hub or cam phaser sprocket are bad. Usually due to oil starvation. It would account for the noise and the codes. Strange, because I literally never heard of these things going bad in S60. BTW, oil is good and was just replaced (with filter) 2 month ago.

UPDATE - So, both solenoids DID fail, due to oil starvation. Solenoids have oil screens. The intake solenoid oil screen was completely plugged. The exhaust solenoid screen was completely plugged with sludge, BUT, a hole developed allowing sludge to enter the solenoid and wrecking it. Engine was hot-flushed and solenoids replaced. No more hesitation, the car gained a LOT of torque. I suggest all of you do this as a preventative measure.