2003 - 2005 BMW Z4 Cylinder Head Assembly - Right (Passenger) (OEM)

What to look for when buying this part:

• Check for cracks or damage.
• Make sure the valve seats are in good condition.
• Inspect the threads for the head bolts.
• Verify the part is the correct one for your vehicle.
• Ask about warranty or return policies.

Quality indicators for the available options:

What's typically included with the part:

• The cylinder head casting
• Valves
• Valve springs
• Valve retainers
• Valve locks

Difficulty level and estimated time:

• Difficulty: High
• Estimated Time: 8-16 hours

Special tools needed (if any):

• Torque wrench
• Head bolt angle meter
• Valve spring compressor
• Socket set
• Wrench set
• Engine hoist (recommended)

Critical steps and tips:

1. Disconnect the battery.
2. Drain the coolant and oil.
3. Remove the intake and exhaust manifolds.
4. Remove the valve cover.
5. Remove the rocker arms (or camshafts).
6. Loosen and remove the head bolts in the correct sequence.
7. Carefully lift the cylinder head off the engine.
8. Clean the cylinder head and engine block surfaces.
9. Install the new head gasket.

Whether DIY is recommended or professional installation is better:

Professional installation is highly recommended due to the complexity and precision required. Incorrect installation can cause serious engine damage.

Used OEM: Best value - genuine factory parts, tested and inspected, at significantly lower prices. These parts offer a cost-effective way to get a reliable replacement.

Refurbished OEM: Factory parts professionally restored with new components. These parts offer a balance of quality and affordability.

New Aftermarket: Brand new third-party parts built to OE specs. These parts offer a new component at a competitive price.

Parts commonly replaced or checked at the same time:

• Head gasket
• Head bolts
• Thermostat
• Water pump
• Timing chain or belt
• Valve cover gasket
• Intake manifold gasket
• Exhaust manifold gasket

Why replacing related parts prevents repeat failures:

Replacing related parts ensures that all components are in good working order and reduces the risk of future failures. For example, a new head gasket is essential when replacing a cylinder head to ensure a proper seal. Replacing the water pump and thermostat can prevent future overheating issues.

How long this part normally lasts:

• 100,000 - 200,000 miles

Factors that affect longevity:

• Regular maintenance (oil changes, coolant flushes)
• Driving habits
• Engine operating temperature
• Quality of replacement parts

Budget vs mid-range vs premium options:

• Used OEM: $300 - $600
• Refurbished OEM: $500 - $800
• New Aftermarket: $600 - $1000

Labor cost considerations if applicable:

• Labor: $800 - $1500 (depending on the shop and location)

Total job cost estimates:

• Used OEM: $1100 - $2100
• Refurbished OEM: $1300 - $2300
• New Aftermarket: $1400 - $2500

Known issues for this vehicle's system related to this part:

• The 4.4L V8 engine in these vehicles is known for potential overheating issues, which can damage the cylinder heads.
• Coolant leaks can occur around the cylinder head gasket.
• Oil leaks can occur from the valve cover gasket.

Any TSBs or common complaints:

• Some vehicles may experience valve guide wear, leading to oil consumption.

How to confirm proper operation:

• Check for leaks (coolant, oil, exhaust).
• Monitor engine temperature.
• Check the oil level and condition.
• Scan for any diagnostic trouble codes (DTCs).

What to look/listen for to verify it's working correctly:

• Smooth engine running.
• No unusual noises.
• Normal engine temperature.
• No white smoke from the exhaust.

FAQ

Q: How do I know if my cylinder head is cracked?
A: Look for white smoke from the exhaust, coolant loss, or milky oil. A pressure test or visual inspection by a mechanic can confirm a crack.

Q: Can I replace just one cylinder head, or do I need to replace both?
A: It is generally recommended to replace both cylinder heads at the same time to ensure balanced engine performance and prevent future issues. However, if only one head is damaged, replacing just that one is possible, but it's important to ensure it matches the specifications of the other head.

Q: What kind of coolant should I use with this cylinder head?
A: Use the coolant specified in your vehicle's owner's manual. Using the wrong coolant can cause corrosion and damage to the cooling system.

Q: What should I do if I over-torque the head bolts?
A: Over-torquing head bolts can damage the threads in the engine block or the cylinder head. If you over-torque a head bolt, it should be replaced with a new one, and the torqueing process should be restarted from the beginning. It's crucial to use a torque wrench and follow the manufacturer's specifications.

Q: What is the difference between a used OEM and a refurbished OEM cylinder head?
A: A used OEM cylinder head is a genuine factory part that has been removed from a vehicle and inspected for damage. A refurbished OEM cylinder head is also a genuine factory part, but it has been professionally restored with new components, such as valves, valve springs, and seals. Refurbished heads are generally in better condition than used heads.

OEM Part Numbers:

• BMW: 11121436790, 11121439724, 11121745458, 11127514540, 11127514543

Fits Years: 2003 2004 2005