Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Cylinder Heads: Notes
The two N73 cylinder heads are a new development from BMW and have been adapted to the new direct injection system. The cylinder heads are equipped with Valvetronic valve gear and Bi-VANOS. The inlet camshaft and the Valvetronic eccentric shaft are jointly guided by a bridge support.
The ports for the high pressure fuel injectors are located on the intake side. The engine is equipped with a high pressure fuel pump for each cylinder head. Each cylinder head has a bucket-tappet drive on the exhaust camshaft for the high pressure fuel pump.
The secondary air ducts for subsequent exhaust gas treatment are integrated in the cylinder heads. The cylinder heads are cooled by the "cross-flow" principle. The cylinder heads are made from aluminum and are manufactured using gravity die-casting.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.