Thursday, November 8, 2012

Mini Cooper S: Rattle Noise from Engine

Mini Technical Service Bulletin SI M 11 02 07 
Update: 2/20/13 - View this TechTip: Mini Cooper s R56 Engine Rattle Noise

Vehicles affected: Mini Cooper "S" R55, R56 all models with the N14 engine produced between 2006 to May 4th 2009.

Symptom: Early symptoms of chain tensioner failure on the R56, R55 is a slight rattling sound from the passenger side of the engine valve cover, even with engine running but not driven.  The rattle sound will increase with speed, but go away when the engine reaches approximately 1800 R.P.M.  The sound will return when the engine returns to lower R.P.M.s during deceleration or idle.  In early stages this sound may be more pronounced at colder temperatures, but in more severe cases the sound and vibration will be heard at all temperatures.

Common Mini Cooper R56 engine failure: This failure is the result of a weak or collapsed timing chain tensioner. If driven for an extended period of time the results will be a broken plastic tensioner rail or upper guide rail.  The noise you are hearing is the loose timing chain resulting from a collapsed timing chain tensioner. 

Update 2/20/2013
 View this new video overview of this Tech Tip or, view the full  
The slapping action of the timing chain will eventually break the tension rails. This condition will also effect cam timing and risk an eventual chain failure. The chain will also need to be replaced at the time of repair in case of stretching or elongation. We do not recommend driving a vehicle in this condition other than at low R.P.M. to a nearby repair shop.

Chain tensioner replacement: The factory Mini service bulletin requires replacing the original tensioner with a new modified version which is 5mm shorter and has a more aggressive tension spring. This is item number 11 31 7 598 956


R56, R55 timing chain and guide rail replacement: The N14 engine is designed to allow replacement of the chain rail, tensioner, and chain assembly without engine removal or major engine disassembly. To do the project you will need to lift the vehicle, remove the valve cover, right engine mount, right front wheel, and crank shaft vibration damper. A special cam timing tool kit is required to lock the cams and crankshaft in a fixed position to allow for replacement of the chain and tensioner assembly.  

To assist in this repair we recommend the Bentley Mini Cooper Service Manual for reference.

R56, R55 Complete Tensioner Chain Kit: Promini offers a complete "R56, R55 Death Rattle" repair kit which includes all the components required to repair your Mini:
- New shorter tensioner
- New timing chain
- New tensioner chain rail
- New guide rail
- New upper support rail
- New valve cover gasket
- New crank shaft sprocket
- 3 New bearing bolts
- 3 New bearing bolt seals

R56, R55, N12, N14 Special Cam Timing Tool Kit:  Promini offers the factory special tools referenced in the official service bulletin required for timing chain replacement for both the Cooper (N12) and Cooper "S" (N14) engines in one full kit:
- Flywheel locating pin (special tool 11 9 340)
- Mechanical chain tensioner (special tool 11 9 340)
- Intake and exhaust cam locks for N12 engine
- Intake and exhaust cam locks for N14 engine


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    Mini Cooper

    1. Awesome, thank you Julie! Wishing you a Happy Holiday. If we can help with anything or have a topic you would like more information on, please let us know.