Diagnostic: Oil leak on BMW - Causes and costs

An oil leak on a BMW (1, 3, 5 Series, X1, X3) shows as stains under the vehicle, falling oil level or burning oil smell. Depending on petrol (B38, B48) or diesel (B47, B57) engines, common leak points and costs differ.

BMW petrol (B38, B48)

On B38 and B48 (turbo petrol), oil leaks are often linked to the sump gasket (under the engine), cam cover (aged gasket), turbo hoses (feed or return) or head gasket. A loose drain plug or oil filter can also weep. Cleaning the engine then driving a short distance helps locate the source.

BMW diesel (B47, B57)

On B47 and B57, common leaks involve the sump gasket, turbo (cartridge, hoses), oil pump or head gasket. Injector seals can leak. A large leak or steadily falling level should be fixed without delay: risk of engine wear or failure.

What to do

Do not drive with a large leak or low level: top up in an emergency to reach a garage, then repair the leak. A professional cleans the engine, locates the leak (sometimes with dye) and replaces the gasket or faulty part.

Order of magnitude for costs

• Sump gasket: about €200–500 (engine or gearbox removal depending on access).
• Cam cover gasket: about €120–300.
• Turbo hoses: about €150–400 depending on access.
• Head gasket: about €1,000–2,500 and more depending on engine.
• Injector seal (diesel): about €80–200 per injector.

My Auto Check-up helps you prepare your visit by gathering information (model, engine, symptoms) for an initial cost estimate.