Attention! Allow the engine to cool completely before loosening the cylinder head bolts.
Note. On vehicles with high mileage during repair work, before removing the cylinder head, check the height of the cams on the camshaft (detailed instructions are given in chapter 2, part B, section 12).
Withdrawal
1. Disconnect the wire from the negative battery terminal.
2. Remove the air filter (see chapter 4, section 8).
3. Remove intake manifold (see section 5).
4. If it is necessary to remove the head of the front cylinders, unscrew the bolt of the probe tube (oil level gauge).
5. Disconnect all vacuum hoses from a head of cylinders. For ease of installation, label each one.
6. Disconnect the wires from the spark plugs and remove the spark plugs (see chapter 1, section 32). To make it easier to connect the ignition wires, label each one.
7. Disconnect the exhaust manifold from the cylinder head to be removed (see section 8).
8. Remove valve covers (see section 4).
9. Remove rocker arms and rods (see section 6).
10. Using a new gasket, circle the contours of the cylinder sections with bolt holes on a piece of cardboard (see illustration). Don't forget to label the front of the engine for reference (from the drive belt). Punch holes at the bolt locations. Loosen the cylinder head bolts 1/4 turn in turn until they can be unscrewed by hand; at the same time, go from one bolt to another in the reverse order of their tightening (see illustration). As you remove the bolts, insert them into the holder made of cardboard: this will ensure that they are installed in the same holes from which they were turned out; this requirement is mandatory.
9.10a. To avoid mixing up the cylinder head bolts, use a new gasket to transfer the threaded hole pattern for these bolts onto a cardboard template, then punch holes in the template and insert the appropriate bolts into them | 9.10b. Cylinder head bolt tightening sequence (loosen these bolts in reverse order) |
11. Detach the head (heads) cylinders from the engine. If you feel resistance, do not try to remove the head using a lever inserted between the head and the cylinder block (e.g. screwdrivers): Doing so may damage the mating surfaces. Again check that all the bolts are loose, then use a block of wood and a hammer to tap the cylinder head and try to remove it again. Be careful as the heads sit on dowel pins. As a last resort, try to detach the head using the lever installed in its rear corner; while trying not to damage anything. After removing the head, place it on wooden blocks so as not to damage the gasket surfaces.
12. Procedures for disassembling and checking the condition of the cylinder head, as well as servicing the cam mechanism, are presented in chapter 2, part 2.3.
Installation
13. Before starting the installation procedure, the mating surfaces of the head and cylinder block should be thoroughly cleaned.
14. Use a scraper to remove any old gasket material from the mating surfaces, then clean with lacquer cleaner or acetone. If grease remains on the mating surfaces during reassembly, the gasket may not seal sufficiently, resulting in oil leakage. When working on the cylinder block, it is recommended to cover the recesses of the pushers with rags to prevent dirt from entering the engine. Remove dirt that has entered the cylinders with a rag or vacuum cleaner.
9.14. After removing the old gasket, carefully remove the remaining sealant and gasket material with a scraper
15. Check the mating surfaces of the block and cylinder head for nicks, deep scratches and other types of damage. If the damage is minor, remove it with a file; in case of severe damage, the only way to eliminate them is to machine the surface.
16. Using a tap of suitable diameter, drive the threads in the cylinder head bolt holes. Using an appropriate die, completely drive the threads on each of the cylinder head bolts (see illustration). The presence of dirt, traces of sealant and damaged threads will affect the torque value.
9.16. Using a suitable die, clean the threads on the mounting bolts before installing the cylinder head
17. Position the new gasket over the dowel pins in the cylinder block. Some gaskets are labeled "TOR" ("Top") And "THIS SIDE UP" ("Upper side"), facilitating the correct installation of the gasket during assembly (see illustrations).
9.17a. Position the new gasket on the side pins (shown by arrows),... | 9.17b....make sure it is facing the correct side up |
18. Carefully place the head on the cylinder block, being careful not to move the gasket.
19. Apply a coat of General Motors N 1052080, Permatex N2, or equivalent to the threads and bottom surfaces of the bolt heads. Make no mistake when tightening bolts: two different sizes of bolts are used to fasten the cylinder head (see illustration). Using a cardboard bolting template will help you complete this procedure correctly.
9.19. Two different sizes of bolts are used to attach the cylinder head; before screwing the bolts, apply to their threads and the lower surfaces of the heads (shown by arrows) sealant layer
20. Tighten the bolts in the recommended sequence (see illustration 9106), until the torque specified in the specifications given in this chapter is reached. After that, in the same sequence, tighten each bolt to the angle specified in the technical specifications.
21. The remaining operations of this procedure are performed in reverse order.
22. Change the oil filter and fill the engine with fresh oil (see chapter 1, section 12).