Spring maintenance service on April 5th was satisfactory. Knocking noise from engine identified the need for lower engine bracket replacement due to piston misalignment. Was advised that parts were on order and car was "safe" to drive until replacement which I was advised would be covered by extended warranty. I telephoned on April 20th to request an update and was advised that some, but not all of the parts had arrived and was assured that Service dept will contact me when remaining parts have arrived. In the meantime, knocking noise has increased in intensity. Telephoned again on May 9th to request an update. Was advised by Service dept that request for replacement under extended warranty had to be approved first by Hyundai prior to ordering of parts. Approval was received this week by dealership and subsequently parts will be ordered this week and are expected to arrive in approximately 2 weeks. This is simply unacceptable - I was not advised that approval was needed prior to replacement. In the age of digital technology, there is no reason why a month is required for approval of a repair that is already covered by an extended warranty. Furthermore, why were parts not ordered in anticipation of the approval reducing the wait. I am now going on 6 weeks with increasingly loud knocking from my engine concerning me to the extent that I limit my car travel to within city limits only lest I need a tow from the middle of nowhere.