The largest online repair guide library for every car

About us
Contact support
FAQ
Sign up
Sign in

Turbocharger Wastegate Rattle & Loss of Power on my 2016 Mini Cooper S

0

Chris P. · rep 0 · May 25, 4:56 AM · 1 replies · solved · Question

Vehicle: 2016 Mini Cooper S Hardtop 2-Door

Hey everyone,

I've been noticing a really annoying rattling sound coming from the engine bay of my 2016 Mini Cooper S Hardtop, especially when I let off the gas. It sounds like a metallic rattle, almost like something is loose. More concerningly, I've also felt a noticeable drop in power, particularly at higher RPMs, and it just doesn't pull like it used to.

I've heard about wastegate issues on these B48 engines. Has anyone else experienced this? Could it be a failing wastegate actuator or something more serious with the turbo itself? I'm trying to figure out if this is something I can check myself before taking it to a shop. No check engine light yet, which is weird given the power loss.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 4:56 AM

0

ClearTheCode admin answer:

It sounds like you're describing classic symptoms of a turbocharger wastegate issue, which is unfortunately not uncommon on some Mini Cooper S models with the B48 engine.

Common Causes:

  • Worn Wastegate Bushings/Actuator: Over time, the components that control the wastegate flap can wear out, leading to excessive play and a rattling sound. This can prevent the wastegate from closing fully, causing a loss of boost pressure and power.
  • Turbocharger Internal Damage: In more severe cases, the wastegate flap itself or other internal turbo components could be damaged.
  • Vacuum Line Issues: Less common, but a leak in the vacuum lines controlling the wastegate actuator could also lead to improper wastegate operation.

What You Can Do (Initial Checks):

  1. Visual Inspection: Carefully inspect the turbocharger area, looking for loose connections, cracked vacuum lines, or obvious signs of damage around the wastegate actuator arm. You might be able to gently try to move the wastegate arm by hand (when the engine is cold) to feel for excessive play.
  2. Listen Carefully: With the engine running, try to pinpoint the source of the rattle. Sometimes a mechanic's stethoscope can help.
  3. Check for Codes (Even if no CEL): A professional scan tool can sometimes pull 'pending' or 'history' codes even if the Check Engine Light isn't illuminated. Look for codes like P0299 (Turbocharger/Supercharger Underboost) or P0234 (Turbocharger/Supercharger Overboost Condition).

When to See a Shop:

  • Immediate Action: If you're experiencing significant power loss, it's best to have it inspected soon. Continued driving with a malfunctioning turbo can potentially lead to further engine damage.
  • Professional Diagnosis: A qualified Mini specialist or BMW-certified technician will have the specialized diagnostic tools to accurately determine the cause. They can perform boost pressure tests, actuator tests, and potentially use a borescope to inspect the turbo's internal components without full disassembly.
  • Repair Complexity: Wastegate repairs often involve replacing the turbocharger assembly or specific wastegate components, which can be a complex job requiring specialized tools and expertise.
Menu

Help & account