dougash

For me, that 'knocking' noise was a precursor to a pressurized oil pump line bursting. The line had actually started leaking (not a lot at first, but increasing until I finally learned what it was), but I could never see any dripping under the car so I didn't realize it was leaking. Apparently that hose is something of an achilles heal issue for the RX. Anyway, once the leak increased and I kept seeing my oil level go down, I took it back to dealer and they found the leak. Once replaced, the knocking went away...