Timing Belt Replacement:
The largest part of 60k maintenance is replacing the items on the front of the engine: timing belt, water pump, seals, etc. Not really a hard job, but very time consuming.
[
Procedure:
1. Disconnect the negative terminal on the battery.
2. Raise the front of the car & put it on ramps or jack stands, observe all safety precessions.
3. Remove the lower engine shield (6 x 10 mm)
4. Open radiator petcock & drain fluid into a bucket (be VERY careful not to scald yourself if the car is warm). Once fluid is draining out into the bucket, open the radiator cap and remove the secondary fill plug on the opposite side of the radiator. Let the radiator drain completely.
5. Remove the lower fan shroud from the upper fan shroud and radiator (3 clips). Remove the lower radiator hose bracket (1 x 10 mm).
6. On turbos, remove the left and right throttle body intake hoses. Put rags into each of the intercooler tubes at the front to keep anything from falling into there (4 hose clamps x 8 mm).
7. Remove the upper radiator brackets (2 x 10 mm)
8. On '93 & earlier Zs, remove the recall power transistor wire wraps from the upper radiator hoses.
9. Remove the upper radiator hose. (2 hose clamps x 10 mm). Disconnect the lower radiator hose from the radiator, let it drain into the bucket. Disconnect the lower radiator hose from the engine. Remove the lower radiator hose. Disconnect the coolant overflow tube from the radiator (1 hose clamp). Check that it's off the radiator shroud down the driver's side. There's a spot it 'tucks' into to hold it in place about halfway down. Make sure the hose isn't allowed to drain, it will empty the overflow reservoir. I generally loop it around a hose on the driver side to keep it from falling down and draining. There are transmission fluid cooler hoses going into the radiator on the driver side on the automatic transmission models. Disconnect them where they come up to the lower radiator hose under the engine and let the contents drain into the bucket.
10. Remove the lower fan shroud (3 x clips). Remove the radiator. On turbos, the intercooler tubes will be in the way, wiggle the radiator around some to get it clear of them. Don't loose the two round rubber mounting grommets on the bottom of the radiator.
11. Remove the fan from the fan clutch (4 x 10 mm). Remove fan clutch assembly from the water pump (4 x 10 mm).
12. Loosen the AC idler pulley (1 x 14 mm) and the adjustment bolt (1 x 12 mm).
13. Loosen the locking bolt (1 x 12 mm), the adjustment bolt (1 x 12 mm) & the pivot bolt (1 x 17 mm) on the alternator. Remove the bolt holding the adjustment bracket to the block, pull the bracket away from the block (1 x 12 mm).
14. Loosen the locking nut (1 x 12), the adjustment bolt (1 x 12 mm) & the pivot bolt (1 x 14 mm through the pulley's hole) on the power steering pump.
15. Remove all the accessory drive belts.
16. Unbolt the top & bottom bolt (2 x 8 mm) on the power transistor bracket, removing the entire assembly. Unplug the engine temperature sensor (yellow w/ the wire clip) & the thermal sensor (black spade plug). Unscrew the bracket holding the harness under the crank angle sensor. On '90-'93s Pull back the rubber shield on the crank angle sensor plug & carefully remove the connector (another wire clip) or on the '94+, just unplug it. Bend the entire front engine wiring harness back out of the way.
17. Remove the plastic upper right timing belt cover (3 x phillips/8 mm, 5 x 5 mm hex head). Try to keep the screws in the appropriate holes. There are a lot of different lengths of bolt and they get easily confused if removed. There's one phillips/8 mm in the lower center of both plastic covers that should be unscrewed last. It's going into a spacer stud behind it and most of the time it backs the stud out instead of leaving the stud there.
18. Turn the crank clockwise using the crank bolt until the dots on the exposed sprockets line up with the dots on the back covers (painted white for illustration purposes. This places the engine's rotation at #1 Top Dead Center (TDC). Don't expect the belt's marks to line up, only the dots on the sprocket and the back cover. Rotate the crank about 10 degrees BeforeTDC (BTDC) (counter clockwise). This makes installing the belt easier later on.
19a. For 5spds, put the car in 5th gear, make sure the parking brake is engaged. Loosen the crank pulley bolt (1 x 27 mm). Make sure to use a real penetrating lubricant beforehand. I recommend Blaster brand. An air wrench makes this much easier.
19b. For autos, if an air wrench is available, try it first to loosen the crank bolt (1 x 27 mm). Make sure to use a real penetrating lubricant beforehand. I recommend Blaster brand. If the air wrench alone doesn't work, or isn't available, here's the alternate method: Use the belt wrapping technique used later on the cam sprockets here. Basically wrap the rear set of grooves on the pulley with the old AC belt and loop the excess over to the bracket of the alternator (it loops around behind the adjustment bolt) to hold the pulley still. Doing this WILL ruin the belt, so make sure it's not going to be re-used.
20. Once the crank bolt is broken loose, loosen it about 1/2" to give the pulley some room to move forward with the bolt still in the threads. Mount the pulley puller on the crank pulley, using the dimple in the head of the crank bolt as the contact point for the puller's center bolt. Clamp the arms on the THICK part of the pulley, not the very front. The pulley is made of soft iron an will break easily if the front lip is used as the arm's contact points. Remove the crank pulley. Be careful with the woodruff key exposed on the crankshaft. Also be extremely careful with the AC condensor (the other radiator looking thing now exposed), it's rather fragile & a a good dent might cause it to leak out all the freon. Not good at all.
21. Move the coolant bucket to front center under the engine. Remove the water inlet tube (lower aluminum tube) (2 x 12 mm nuts, 1 X 6 mm hex head). Use a screwdriver to remove the thermostat. Be careful not to scratch the mating surfaces.
22. Squeeze the clamps on the water outlet tubes, push them back onto the rubber hoses. Remove the water outlet tube (3 x 6 mm hex head). Remove all 4 clamps, remove both short water hoses.
23. Remove the plastic upper left timing belt cover (2 x phillips/8 mm, 5 x 5 mm hex head). Remember the one phillips/8 mm that's going into the spacer stud. Try to keep the screws in the appropriate holes. There are a lot of different lengths of bolt and they get easily confused if removed. Remove the metal lower timing belt cover (6 x 8 mm). If the spacer studs didn't come off with the plastic timing belt covers, remove them now (2 x 17 mm bolts)
24. Remove the water pump (6 x 12mm) Clean off all the coolant fittings with a putty knife to ensure a good seal when replacing the parts. Be careful not to scratch the mating surfaces while cleaning off the old sealer. A small wire brush will quickly remove old sealer without damaging the mating surfaces.
25. Remove the Crank angle sensor mounting bracket ( 3 x 12 mm) and crank angle sensor
26. Loosen the exhaust cam sprocket bolts (8 x 11 mm)
27. Remove the intake cam sprocket front covers (8 x 7 mm) there is a spring & O-ring behind the cover for the Variable Valve Timing on the '90-'95s, don't drop them. A small amount of oil will leak out from the inside of the sprocket, this is normal.
28. Jeff's auto-tensioner was almost at full extension. Take one of the 10 mm bolts from the fan and screw it into the retention hole on the tensioner. When it's slowly tightened, it will be long enough to remove the tension from the belt. Remove the belt auto-tensioner (2 x 12 mm bolts, 1 x 12 mm nut). Loosen the nut first , then remove the bolt to the left, then the bolt to the right. Remove the timing belt. Use the old belt to wrap around each sprocket to control them while letting them come to rest. The cams will want to rotate a few degrees rather violently, try to avoid this because the VG30DE(TT) engine is low tolerance & the valves can make contact with the pistons under certain conditions. Always be careful around the cam sprockets when the timing belt is not on them and under tension. The cam lobes will want to relieve spring tension whenever possible. When the sprockets turn, the valves are coming to 'rest' in their seats. It's actually a good thing most of the time. The passenger side cams will definitely rotate. The drivers side cams are already settled.
29. Remove the intake cam sprockets (2 x 19 mm). The intake cam sprockets changed in '94, the newer ones are silver and beefier looking (FWIW they are also adjustable).
30. Remove the exhaust cam sprockets (8 x 11 mm)
31. Remove the upper middle idler pulley (1 x 14 mm).
32. Remove the back metal covers to access the cam seals (8 x 10 mm). There might be a stud on the either side to remove if it didn't come off with the plastic cover.
33. Remove the seals by carefully bending the outside ring with a punch or screwdriver. DO NOT scratch the camshaft or outer sealing surface. Just barely dent the seal enough to get a screwdriver over the top & be able to pry down a little bit to pop it out. I can not stress enough how important it is to NOT scratch any of the mating surfaces. Scratching the cam will lead to VERY EXPENSIVE repairs because the seal will leak oil out into the timing belt area. Not something I care to think about. If a seal puller is available, it can be used on the intake cam seals, they don't seal to the camshafts, so the puller can be inserted and used.
34. Carefully clean the cam shaft & head mating surfaces with a rag. Lightly oil the new seal with motor oil inside & out. Slip the new cam seal over the end of the camshaft with the 'solid' side facing outward. Gently push the seal into place, then use one of the old seals (cleaned) as a spacer to tap the new seal in place using ONLY a plastic face mallet to avoid scratching/damaging the camshaft.
35. Use a pry bar to slide the crank sprocket & washer off the crank. Be careful with the woodruff keys exposed on the crankshaft. If the sprocket doesn't come off, the simplest solution is to just cut it off. This is where the new crank sprocket and rear washer come into play. I don't waste time trying to heat it up etc. Striking it with a metal hammer is not a good idea either as the sprocket's metal is very soft and the teeth on the sprocket will become flat without much effort. With the gear at top dead center, cut through the gear over the key way with a 4" air cut-off wheel. Just slice across it being careful to not nick the crank or cut into the aluminum oil pump assembly behind it (too badly at least). Once a sufficient slot is cut, hammer a chisel into the slot. The sprocket will eventually crack over the keyway and then it will easily slide off.
36. Remove the front main seal the same way as the cam seals. Replacing the main seal is MUCH more difficult then the cam seals because of the shape of the crankshaft itself. There is a step the seal must get over to start to seat. All of the front seals have a tiny tension spring inside the seal, this spring doesn't stay seated very well while installing the seal. There is an easy way to do it with an additional 'tool' and a harder way to do it without.
Easy way: Get some thin Lexan plastic, cut a 4.5" x 3" rectangle out of it. Oil up the seal inside and out, then roll it up and slip it into the seal. Take this and slip it all over the crank and push it up into the seal's seat. The idea is to use it as a ramp over the step on the crank & into position without rolling over the seal and letting the spring in the seal loose. Use another old seal and slip it over the plastic and use it as a spacer to tap the new seal in place. once everything is seated, pull the old seal off the plastic, then gently pull the plastic out of there. If everything is lubed up, it should slip right out, leaving the seal perfectly seated and the spring on the inside remaining on the inside. I've used it several times now. Just make sure the seal is going in with the 'solid' side facing forward like the others.
Seat the crank seal the same way the cam seals were seated. Run a finger all the way around the seal to make sure it is seated evenly, the bottom of the seal can't be seen without an inspection mirror.
37. Install the washer & the crank sprocket over the woodruff keys on the crank shaft. The flat washer goes on the back side of the sprocket. If the lower belt cover loops around the crank, then a second flat washer goes on the front of the sprocket. If the lower belt cover doesn't loop around the crank, the bevel edged washer goes on the front with the bevel facing the rear to make the belt fall back onto the sprocket if it were to come forward.
38. Install the metal back covers (8 x 10 mm).
39. Clean off the ends of the intake cams. Install the exhaust cam sprockets (8 x 11 mm). The sprockets are self keying on the metal dowel pins. Just hand tighten the bolts for now.