Cylinder heads — removal and installation

Warning: Wait until the engine is completely cool before beginning this procedure.


1. Drain the cooling system (see Tune-up and routine maintenance).

2. Remove the intake manifold (see Intake manifold and Valve Lifter Oil Manifold (VLOM) — removal and installation).

3. Remove the fuel rail (s) from the cylinder head(s) (see Fuel and exhaust systems).

4. Remove the valve covers (see Valve covers — removal and installation).

5. Remove the rocker arms and pushrods (see Rocker arms and pushrods — removal, inspection and installation).

6. Refer to Section Exhaust manifolds — removal and installation and disconnect the exhaust manifold (s) from the cylinder head(s).

7. If you’re working on the right cylinder head, remove the drivebelt, air conditioning compressor belt (see Tune-up and routine maintenance) then the alternator (see Engine electrical systems).

8. If you’re working on the right cylinder head, remove the idler pulley bolt then remove the alternator and air conditioning compressor bracket (see illustration).

9.8 Alternator and air conditioning bracket mounting bolt/stud locations — right side cylinder removal only

Chevrolet Silverado V6 engine 4,3L _ Alternator and air conditioning bracket mounting bolt/stud locations - right side cylinder removal only

9. Remove the spark plugs.

10. Loosen the cylinder head bolts in 1/4-turn increments until they can be removed by hand. Work from bolt-to-bolt in a pattern that’s the reverse of the tightening sequence shown in illustration 9.25.

Caution: Discard the bolts and obtain new ones for installation.

11. Lift the cylinder head (s) off the engine. If resistance is felt, DO NOT pry between the cylinder head and block as damage to the mating surfaces will result. To dislodge the cylinder head, place a block of wood against the end of it and strike the wood block with a hammer. Store the cylinder heads on wood blocks to prevent damage to the gasket sealing surfaces.


12. The mating surfaces of the cylinder heads and block must be perfectly clean when the cylinder heads are installed.

13. Use a gasket scraper to remove all traces of carbon and old gasket material, then clean the mating surfaces with brake system cleaner. If there’s oil on the mating surfaces when the cylinder heads are installed, the gaskets may not seal correctly and leaks may develop. When working on the block, cover the lifter valley with shop rags to keep debris out of the engine. Use a vacuum cleaner to remove any debris that falls into the cylinders.

Caution: The cylinder head and cylinder block are made of aluminum and can easily be dam- aged by using a scraper or sanding the surfaces.

14. Check the block and cylinder head mating surfaces for nicks, deep scratches and other damage. If damage is slight, it can be removed with a file — if it’s excessive, machining may be the only alternative.

15. Use a tap of the correct size to chase the threads in the cylinder head bolt holes. Dirt, corrosion, sealant and damaged threads will affect torque readings.

16. Position the new gaskets over the dowel pins in the block with the marks UP on top.

Note: Composition-type gaskets are used on most engines, with a thin sheet metal core. Be very careful when handling because the edges may be very sharp. Composition gaskets do not require sealant.

17. Carefully position the cylinder heads on the block without disturbing the gaskets.

18. Purchase NEW cylinder head bolts.

19. Install the new bolts and tighten them finger tight. Follow the recommended sequence and tighten the bolts in several steps to the torque and angle of rotation listed in this Chapter’s Specifications (see illustration).

9.19 Cylinder head bolt TIGHTENING sequence

Chevrolet Silverado V6 engine 4,3L _ Cylinder head bolt TIGHTENING sequence

20. The remainder of installation is the reverse of removal.

21. Change the engine oil and filter and fill the cooling system with the proper coolant (see Tune-up and routine maintenance), then start the engine and check carefully for oil and coolant leaks.

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