We just completed a full service on a 2001 Volvo S60 2.4T with 148k miles. The vehicle had a minor head gasket leak into the oil, not so much to fully contaminate the oil, but enough to leave a residue on the oil cap. Upon further inspection, we found the crankcase breather plugged and the oil separator part of the system full of orange goo.

We removed the cylinder head and oil pan, had everything cleaned checked and then back together it went. We noticed upon reassembly that the VVT hub did not rotate even when a bit of force was used. These years typically have a spring-loaded VVT but this one was seized.

After getting a new VVT unit and getting the car back on the road, I made the call to open up the old unit. I've never seen the inside of Volvo's VVT so I wanted to share with all.

I started by grinding off the rivets on both sides of the VVT hub assembly. Doing one side didn't release the sections and it appears that they use a tapered rivet that is peened over. Basically grinding the peened side would have been enough.

Now, the inside of the unit is different from most other vehicles.

The working mechanism is a series of three spiral gears that move together and rotate the assembly as oil enters the chamber. While I didn't find any "smoking gun" when I opened it up, my best assessment was that there was a lot of play in the center hub and it interfered with the torque required to rotate the unit.