Howdy folks,
I recently picked up a GMEPP Extended Warranty from Dennis Fichtner at Denny Menholt Chevrolet [Great guy to deal with! Quick response time, accurate and excellent pricing]. My CTS is the base model with the 2.0 liter 4 cylinder turbocharged engine. It has 59,000+ miles. After reading the Extended Warranty, I noticed the clause regarding performing required Maintenance. So, since I am near 60,000 miles, I changed out the spark plugs and air filter. I perform most of the standard routine maintenance on all 3 of my autos, but I was certainly surprised when I went to do what I figured would be a 20 minute job, due to the engine being a small 4-cylinder. I guess I was remembering my late AMC Gremlin's easy 4-cylinder spark plug change. The CTS requires you to remove the plastic engine cover [Remove one hex-head bolt, remove engine oil fill cap, lift the cover up and pull it towards the front of the car]. Or, if you are impatient as I was, you pull up on the plastic cover, and find that GM glued a sound deadener strip to the back of the cover, causing the cover to refuse to come out of its holes at the rear of the engine, so you lift up more, and snap off one of the retaining legs at the back of the cover, and end up super gluing it back on.Then you take a 10mm socket and loosen the retaining bolt on the coil pack, slide the red electrical connection retainer to the left, and pull the wiring connectors apart. Twist the coil pack clockwise and counterclockwise a few times to loosen the grip on the spark plug, and pull the coil pack straight up. I didn't rotate the coil pack on cylinder #2, and the top of the coil pack pulled loose from the rubber flange that connects the coil to the electrode running down the tube to the plug. When that happened, the coil pack came off in my hand, and a small white fuse flew out under spring pressure and ended up on the concrete below. I ended up pulling the electrode off of the plug with a pair of pliers, and super-gluing the rubber flange back onto the coil pack. The fuse fits into the top of the electrode between the coil pack and the coiled spring that forms the electrode that connects the coil pack to the spark plug. Plug #4 requires you to remove two 10mm bolts from the sound deadener strip at the rear of the engine, so that it can be lifted up, allowing access to the 10mm coil pack of cylinder #4, and allowing the coil pack to rotate slightly and be pulled out of the head. I used Nickeleaze anti-seize on my new plug threads, and placed a shot of Dielectric Grease inside the coil pack electrode boot, then verified my gaps and installed 4 new plugs in their holes hand-tight, then torqued each one to 14 ft. lbs. Reinstalled all 4 coil packs, hit each coil pack wiring connector with a small smear of Dielectric Grease and reconnected them, and reinstalled my plastic engine cover. Started the CTS and test drove for idle and acceleration. Everything works well, but I know why the dealer asked for $275 to do this job. It is easy, but time consuming if getting everything cleaned and lubed is important to you, especially if you break a part or a coil pack separates when you pull it off the plug. It helps to have either a plug socket with the rubber grommet inside to hold the plug in place, as well as a long extension for your ratchet, or use a magnet inside the socket to keep the plugs from falling and getting damaged. The plug holes are deep into the head. Also helps to have a 10mm ratcheting box-end wrench to remove/install the two 10mm bolts that hold the sound deadener in place at the rear of the motor. Very little clearance there, unless you choose to pop the plastic rivets out and remove the deadener fabric, so that the plastic strip can be lifted up enough to give a ratchet wrench clearance.
Hope this helps someone on a future change-out!
Amanda