One morning this past winter, a friend”s 2003 Chevrolet Cavalier cranked but failed to start. The starter seemed to be running free, as if under no load. Removal of the valve cover revealed a very loose timing chain. This post will cover removal of the valve cover and a front engine tear down. Then the chain and associated components will be removed and inspected. Correct cam, piston and crank timing will be re-established. A new kit of timing parts will be installed. Then we will re-assemble and test the work. There is always the possibility, on an interference engine like this, that valve damage may have occurred. A leak down test is ideal here, but we did not have the equipment. We also felt confident that the chain coming loose on start-up made valve damage unlikely, as opposed to under load. This is a challenging repair (we got a $1200 estimate) but we completed it successfully and I wish you good results if you tackle this job. The job at a glanceTools: Floor or scissors jack, supports, 10,13 15,18 and 21 sockets, all sizes of ratchets, socket extension bars,universal socket adapter, 10mm allen wrench modified to 3cm, large straight blade screwdriver, pry bar for locking the crank pulley, torque wrench, (inch and ft lb) 10″ long 10mm and 15mm box end wrenches, 18mm and 24mm wrenches, breaker bar(s) Materials: Lacquer thinner, motor oil, oil catch panParts: Timing chain kit (Cloyes 9-4201S), timing cover gasket (Fel-Pro TCS46041), crank pulley bolt, valve cover gasket set (Fel-Pro VS50596R), if needed. Cost of parts: Timing kit $129.53, timing cover gasket $23.86, crank bolt $7, valve cover gasket, if needed, $25.27Time: 15-20 hours
1) Disconnect the battery. Safety first.2) Remove two 10mm nuts mounted on studs in the driver”s side of the valve cover. These secure the metal fuel lines.
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|Remove these two 10mm nuts first|
3) Loosen but don”t remove the studs. There are two 13mm nuts welded onto these studs. Now there will be room to move the throttle cable bracket to allow clearance for the coil pack to be removed.4) Unplug the wiring connector to the coil pack assembly.5) Remove the four 10mm coil pack mounting bolts.6) Wiggle and lift out the coil pack. The throttle cable bracket should be loose enough to get past now.7) Remove the throttle cables from the bracket. The bracket will come along with the valve cover.8) It will be helpful to remove two 10mm nutted studs securing the fuel rails at the radiator side of the engine. This provides more wiggle room to disengage the fuel lines from the brackets.9) Unclamp and remove the rubber hose going to the air intake above the throttle body. Be careful here as I broke it off of the air intake box. I would recommend removing the air intake.10) Loosen and then remove all 14 of the 10 mm bolts holding the valve cover. There are four in the middle now visible with the coil pack removed.
|There are four more under the “Ecotec” labeled coil cover|
11) Tap on the cover with a rubber mallet. Use a small prybar at reinforced points on the cover to gently…and I mean gently, work the cover loose. Gentle repetition pays off. Listen for that little “pop.”
|Take care to gently pry at a place with some “meat” on it|
12) Pull the cover up and now remove the 13mm stud on the firewall side. There is a ground lug behind it that must come off. The front (radiator side) stud can stay on with the throttle bracket.
|The 13mm stud (on the left) must be removed, the other only loosened.|
13) Lift and pull the valve cover off the engine, moving it toward the passenger side. Now the chain can be inspected. This one was extremely loose.
|That”s way too loose to work (guide removed for clarity).|
2)Break the lug nuts on the right front wheel and jack it up, remove the wheel and set it down on a block of wood or a stand.
3) Remove the wheel well splash guard. This is complicated piece held in by 6-8 8mm hex head screws, and two panel fasteners. There are also several wires attached to the piece that need to be removed from holders. Keep track of all fasteners and the positions of wires to ensure efficient and complete re-assembly.
4) Remove the serpentine belt by inserting a 3/8″ ratchet directly into the square hole (from below) and and rotating upward. Hold it there while slipping the belt off.
5) Remove the harmonic balancer (crank pulley) bolt. Jam a pry bar between one of the three cross arms of the balancer and the top of the steering knuckle and lock it in place. Place a 21mm socket on the bolt and use the biggest breaker bar you can get to break the bolt. I used a 24″ bar. There is plenty of turning radius to break this highly torqued bolt. It turns off in the conventional counter-clockwise direction.