Had routine oil changed on 2006 Civic at dealership. Oil appeared to leak following this service (evidence on surfaces under car). Took car to independent mechanic that discovered the Honda dealership that changed the oil did not put washer back in place; had to drain newly replaced oil and add washer at an additional cost. At this time it was also discovered something else was leaking... Leak appeared to come from around the pulley area (front passenger side behind wheel well) and independent mechanic suspected a pulley leak. Independent mechanic thought there was a recall from Honda on this pulley. Paid $105 at Honda dealership to investigate leakage further and they informed that oil was leaking from the timing chain cover plate and appears to have been leaking for a while. (There was no evidence prior to oil change that this was leaking as far as seeing any spots on the surface under the car). Now they want $700 to fix! What would cause the seal to fail on a 2006 Civic that has been serviced regularly and why didn't the dealership notice this earlier?