BMW Turbo Downpipe Gasket 4.5" - B58 - 18328612538

OE replacement turbo-to-downpipe exhaust gasket (4.5") for all BMW B58 turbocharged engines and the Toyota GR Supra. Direct replacement for BMW OE part #18328612538. This crush-style gasket seals the turbocharger exhaust outlet connection, preventing leaks and maintaining exhaust efficiency. Single-use - replace whenever the exhaust connection is separated during service.

Gaskets Required Per Vehicle

All vehicles listed below use a single-turbocharger B58 engine and require 1 gasket per vehicle. Sold individually - order 1 gasket per turbo outlet.

Specifications

Vehicle Fitment

What's Included

• 1x Turbo-to-downpipe gasket (4.5", OE #18328612538)

One gasket per vehicle - all listed engines are single-turbocharger.

Why Replace This Gasket?

This is a single-use crush seal and should not be reused. The gasket deforms on initial installation to create the seal - once compressed, it cannot create the same airtight bond a second time.

Reinstalling an old gasket can cause:

• Exhaust leaks at the turbo-to-downpipe connection
• Reduced engine efficiency and turbo response
• Unwanted exhaust noise, ticking, or hissing
• Check engine lights from O2 sensor readings

Always replace with a new gasket during exhaust, downpipe, or turbo service.

Need a Different Size?

OneFastShop offers turbo-to-downpipe gaskets for other BMW turbocharged engines:

• 3.5" Gasket (OE #18307553601) - for N54, S55, S58, N63, S63, S68, N74 engines (M3, M4, M5, M8, X5M, X6M, 750i, etc.)
• 4" Gasket (OE #18307581970) - for N20, N26, N55, B46, B48 engines (228i, 230i, 320i, 328i, 330i, 428i, 430i, 528i, 530i, M2 F87, X1, X3, MINI Cooper, etc.)

Match the gasket size to your engine before ordering.