BMW E38/E39 LS Swap Info

The BMW E38 (7 Series, produced from 1994 to 2001) is a classic luxury sedan, but like many older European cars, it has its share of engine-related issues. These depend largely on the engine variant—inline-6, V8, or V12—but several problems are fairly common across the board due to age and design quirks.

Here’s a breakdown of common engine issues by type:

🛠️ General E38 Engine Issues (All Variants)

  • Cooling System Failures

    • Radiators, water pumps, thermostat housings, and plastic expansion tanks are notorious for cracking and leaking. Overheating can cause head gasket damage if not addressed quickly.

  • Oil Leaks

    • Valve cover gaskets, oil pan gaskets, and timing covers often develop leaks with age.

  • Vacuum Leaks

    • Cracked vacuum lines and intake boots cause rough idling, misfires, or lean running codes.

  • PCV (Crankcase Ventilation) System Failure

    • Causes oil consumption, rough running, and smoke from the exhaust.

🔩 By Engine Type

1. M52 / M54 (Inline-6, in 728i/728iL)

  • VANOS Seal Wear

    • Causes rough idle, loss of low-end torque, and poor fuel economy.

  • Cooling System (Again)

    • Thermostats and radiators often fail.

  • DISA Valve Failure (M54 only)

    • A broken DISA flap can get sucked into the intake, damaging the engine.

2. M60 / M62 V8 (in 735i/740i/740iL)

  • Timing Chain Guide Failure (M62)

    • Plastic guides become brittle and break down, causing a rattle and eventually total engine failure if ignored.

  • Secondary Air Pump Failure

    • Triggers check engine light; part of emissions system.

  • Intake Manifold Gasket Leaks

    • Causes rough idle and lean codes.

  • Cooling System Weaknesses

    • Especially prone in V8s due to higher heat generation.

  • Oil Separator (PCV) Issues

    • Results in smoke and increased oil consumption.

3. M73 V12 (in 750i/750iL)

  • Intake Manifold Gasket Leaks

    • Tougher to fix due to complexity of V12 layout.

  • Throttle Body Sync Issues

    • Each bank has its own throttle body, and desync causes idle or drivability issues.

  • Coolant Pipe Leaks

    • Central coolant pipe under the intake is known to leak.

  • Cost and Complexity

    • Repairs are difficult due to lack of space and part availability.