The cylinder head gasket seals the seam between the top component of the engine, the cylinder head, and the bottom end, cylinder block or crankcase. It is responsible for sealing the combustion chambers, the oil passages and the coolant away from each other. The sealing surfaces of the cylinder head and cylinder block are machined very precisely to be absolutely flat. The head gasket is designed to fill any irregularities that the machining left behind. In addition, the metal parts expand and contract due to thermal changes, and they do so at different rates because they are made of different metals. This means that the head gasket is required to allow some slippage and to fill distortions between the sealing surfaces even though the entire assembly is bolted together at very high torque.
Cylinder head bolts are designed to stretch and stay stretched when torqued and are therefore one-time-use bolts. They are threaded into the soft alloy of the cylinder block, which, due to the thermal stresses of the engine, may lose its ability to hold the bolts tightly.
Therefore, with aging and mileage, the head gasket may fail. When this happens, you could have engine overheating, oil and coolant mixing along with a poor running motor. On BMW E46 models it is often the case that you cannot simply replace the head gasket; faulty threads in the cylinder block make this a useless repair. Before repairing a faulty head gasket, attempt to re-torque the cylinder head bolts. See our tech article On Cylinder Head Bolt Testing. If the bolts will not tighten, the block is faulty as well. Not all hope is lost as you can repair the thread holes with time-serts, which work quite well. However, most times, if the cylinder head bolt threads are faulty, it is better to go with a used lower mileage engine.
To replace the head gasket, you need a handful of special tools not limited to but including:
Camshaft timing tools
Torque wrench
Angle finder
Plastic clean up tool
Standard hand tools
Be sure to have your cylinder head professionally cleaned and pressure tested before reinstalling.
Read through the entire procedure before beginning. Be sure this is not above your skill level, as engine damage can occur if engine timing is not correct.
Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches.
Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If you are working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Do not work on your vehicle if you feel the task is beyond your ability.
Vehicle models change and evolve, as they grow older, so the vehicle shown in our illustrations may vary slightly from yours. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.
The majority of the procedure will be shown on an engine that is not installed in a vehicle. The steps are the same as if it was installed.
Drain the engine oil and coolant.
Disconnect the negative (-) battery cable. See our tech article on battery replacing for connection notes.
Remove the engine covers. See our tech article on removing engine covers.
Remove the valve cover. See our tech article on valve cover gasket replacing.
Remove the engine cooling fan and shroud. See our tech article on engine cooling fan replacing.
Remove the exhaust manifold. See our tech article on exhaust manifold replacing.
Remove the intake manifold. See our tech article on intake manifold replacing.
Read the Full Article:
www.pelicanparts.com/BMW/tech...
Time: 12 hours
Tab: $250
Tools: Set of sockets hex, Allen, Torx, wrenches (19mm, 32mm), screwdrivers, camshaft timing tools. BMW special tool 11 6 180, 11 2 300, 11 3 240, 11 4 220, 11 6 150
Parts Required: Head gasket kit:, coolant pipe and O-rings, sealing compound 3 Bond 1209
Hot Tip: Work with a cool engine.
Performance Gain: Repair oil and coolant leaks
Complementary Modification: Replace VANOS oil line: www.pelicanparts.com/BMW/tech...
Applicable Models:pelicanparts.com/catalog/SuperCat/BE46_catalog.htm
BMW 323Ci Coupe/Conv (1999-00)
BMW 323i Sedan/Wagon (1999-00)
BMW 325Ci Coupe/Conv (2001-06)
BMW 325i/xi Sedan/Wagon (2001-06)
BMW 328Ci Coupe (1999-00)
BMW 328i Sedan (1999-00)
BMW 330Ci Coupe/Conv (2001-06)
BMW 330i/xi Sedan (2001-06)
26 фев 2020
