The BMW E90 and E92 M3 are iconic vehicles, renowned for their high-revving S65 V8 engine. This naturally aspirated masterpiece delivers exhilarating performance, but like any high-performance engine, it requires diligent maintenance. One crucial aspect of S65 engine care is addressing the rod bearings. While robust, the S65 engine is known to have potential issues with rod bearing wear over time, especially in track-driven or high-mileage vehicles. Proactive replacement of these bearings can significantly extend the life and reliability of your S65, preventing potentially catastrophic engine damage. This guide provides a detailed, step-by-step walkthrough for performing an S65 rod bearing replacement as a DIY project.
Disclaimer:
Undertaking this DIY project is done entirely at your own risk. Automotive repair can be inherently dangerous, and improper procedures can lead to serious damage, injury, or even death. This guide is for informational purposes only and should be considered theoretical advice. If you are not comfortable with complex mechanical work or lack experience with automotive tools and procedures, it is strongly recommended to seek professional assistance from a qualified mechanic. Incorrectly performing this procedure could damage your engine, vehicle systems, void your warranty, or create hazardous conditions. Proceed with caution and ensure you have a thorough understanding of each step before attempting it yourself.
Introduction: The Importance of S65 Rod Bearing Maintenance
The BMW S65 engine, found in the E90 and E92 M3 models, is a high-performance marvel. Its responsive throttle, impressive power band, and signature sound have cemented its place in automotive history. However, a known vulnerability within the S65 engine is the potential for premature wear of the connecting rod bearings. These bearings are critical for crankshaft and connecting rod function, ensuring smooth operation and preventing metal-on-metal contact. Over time and under demanding conditions, the original equipment manufacturer (OEM) rod bearings in the S65 can wear down, leading to increased clearances and potentially catastrophic engine failure.
Replacing the rod bearings is a preventative maintenance measure that many S65 owners undertake to ensure the longevity and reliability of their engines, especially if the vehicle is used for track days or spirited driving. This DIY guide will walk you through the process of replacing the rod bearings in your S65 engine, offering a detailed, photo-illustrated approach to empower you to tackle this job in your own garage.
The Patient: 2011 E90 M3 DCT
Our subject vehicle is a 2011 E90 M3 equipped with a DCT transmission, purchased with 36,000 miles. This particular M3 is a ‘stripper’ model, meaning it’s a no-frills car focused on performance, featuring cloth seats, no navigation, and a slicktop – ideal for its intended purpose: track domination in the upcoming season. Before hitting the track, addressing the rod bearings is a top priority.
Special Tools and Hardware for S65 Rod Bearing Service
To successfully complete an S65 rod bearing replacement, you’ll need a specific set of tools and hardware. Having these ready before you start is crucial for a smooth and efficient process.
Special Tools:
- 3/8” 12-point Socket: Essential for installing the BE-ARP rod bolts. A 12-point socket is necessary to properly torque these bolts.
- 6-inch T30 Torx Bit: A 6-inch length is critical to access some oil pan bolts. A shorter 4-inch bit will not work and can cause significant delays.
- 12-point 12mm Socket: For removing the original equipment manufacturer (OEM) rod bolts.
- Two Electronic Torque Wrenches (Computorq3 or equivalent): It’s highly recommended to use accurate torque wrenches for this job. Having both a 3/8” and 1/2” drive torque wrench will cover the required torque range. Inaccurate torque wrenches can lead to improper bolt tension and potential engine damage.
- Harbor Freight Engine Hoist (or equivalent): A basic engine hoist to support the engine while the subframe is lowered.
- Snap-on 3/8 Electric Ratchet (or Milwaukee equivalent): An electric ratchet will significantly speed up the removal and installation of numerous bolts in this procedure.
Special Hardware:
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BW Street/Track (Group N) Engine Mounts: While optional, upgrading engine mounts is recommended, especially for track cars. For street cars, OEM engine mounts are a suitable replacement.
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BE Bearings Rod Bearings: Considered by many as the premier aftermarket rod bearing solution for the S65 engine.
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BE-ARP Rod Bolts: These are highly recommended over OEM bolts due to their superior strength and the elimination of angle-torqueing in a tight space. While more expensive, they offer significant peace of mind.
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Plastigauge (Green): Used to measure bearing clearance. The green Plastigauge is the correct specification for this application.
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Essential and Recommended Parts (Part Numbers Courtesy of ///Mobbin):
- 11137841085 – e92 m3 oil pan gasket (Essential)
- 11417839832 – pickup tube o-ring (Essential)
- 11417839833 – pickup tube o-ring (Essential)
- 11417838534 – suction pipe gasket
- 11427837997 – oil filter kit (oil filter, o-rings, crush washers)
- 07119904550 x 2 – oil pan drain plug (includes crush washer also)
- 07-12-9-905-537 – 16 x oil pan screws
- 07-12-9-905-599 – 12 x oil pan screws
- 07-12-9-905-600 – 2 x oil pan screws
- 12611744292 – oil level sensor o-ring
- 11812283798 – engine mounts (might include nuts, not sure)
- 07119904025 x 4 – engine mount nuts
Time Commitment for DIY S65 Rod Bearing Replacement
This DIY rod bearing replacement took approximately 12 hours for a first-time attempt. This timeframe included pauses for photo documentation and troubleshooting. With experience and without stopping for photos, the process could likely be completed in significantly less time. A snag with an incorrectly sized Torx bit added an unexpected delay, highlighting the importance of having the correct tools on hand.
Crucial Torque Specifications for S65 Engine (Courtesy of E92love)
Accurate torque specifications are vital for proper assembly and engine function. Refer to these values throughout the reassembly process.
- Oil pan bolts (30 qt) and all other M6 bolts inside/outside engine: 10 Nm
- Steering rack bolt on step 6 (1 qt) (M8): 21 Nm
- E12 transmission to oil pan bolts (4 qt) (M10): 38 Nm
- Engine mount nuts (1 top, 1 bottom on each side): 56 Nm
- Front subframe bolts (6) (M12): 108 Nm
- Rear subframe bolts (2) (M10): 56 Nm + 90 degrees
- Reinforcement plate bolts (7 qt) (M10): 56 Nm + 90 degrees
- Water pump pulley bolts (4) (M6): 10 Nm
- Pulley tensioning system bolts (both sides, 2 each) (M8): 19 Nm
Acknowledgements:
Special thanks to Kurt, Philip, Ryan, and Bert&Ernie from BE Bearings for their invaluable technical assistance and support. Your willingness to answer questions and provide guidance is greatly appreciated.
A special mention to GearHeads International in Rhode Island. For DIY enthusiasts without access to a lift or specialized tools, GearHeads offers a fantastic solution: climate-controlled bays equipped with lifts and a comprehensive array of Snap-On and GearWrench tools. Ron, the owner, provides a welcoming and helpful environment, making complex DIY projects accessible even during winter months. GearHeads is highly recommended for any automotive enthusiast looking for a professional DIY workspace.
Important Notes Before You Begin Your S65 Rod Bearing DIY:
- Oil Refill: A standard oil change for the S65 engine requires approximately 8 quarts/liters of oil. However, during a rod bearing replacement, a significant amount of oil that typically remains within the engine is drained. Therefore, you will need closer to 9.5 bottles of oil to refill the engine adequately. It’s wise to have extra oil on hand just in case.
- Image Order: Some DIY photos may appear slightly out of sequence with the written instructions. This is because the process sometimes involves experimentation and adjustments. Always follow the written step-by-step instructions provided in this guide.
- Rod Bearing Break-in: New rod bearings do not require a specific break-in period. If assembly lube is used, it is recommended to change the engine oil after a few thousand miles. This recommendation is supported by both BE Bearings and Bimmerworld. Rod bearings should ideally operate with a hydrodynamic oil film and not have direct contact with the crankshaft journal under normal operating conditions.
- Dinan Underdrive Pulley Note: If your S65 engine is equipped with a Dinan underdrive pulley set, you will need to rotate the engine via the alternator pulley, which can be done counterclockwise.
Step-by-Step S65 Rod Bearing Replacement Guide
1. Preparing the Vehicle:
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DCT Transmission in Neutral (DCT Models): For M3s equipped with a DCT transmission, the first step is to put the car in neutral. Manual transmission (6MT) owners can skip this step.
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Lift the shift boot from the front by pressing rearwards and unclipping it.
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Locate the black guard visible in the picture. Use a screwdriver to move it forward, allowing it to slide out of the way.
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The white lever behind the black guard is now accessible. Insert a screwdriver and move the lever. The car will shift into neutral, accompanied by an audible alert.
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Install Engine Support Brace: Properly supporting the engine from above is critical before lowering the subframe.
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Install your engine support brace across the engine bay. Slightly tension it upwards to provide gentle upward pressure on the engine. Remember, the engine mounts are still in place, preventing significant engine movement at this stage.
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To protect the hood and minimize potential energy, place a cushioned mat on top of the engine support bar’s sharp points before carefully resting the hood on it.
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Remove Front Wheels: Safely lift the front of the vehicle and remove both front wheels to access the undercarriage.
2. Underbody Panel Removal:
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Remove Felt Underbody Panels: Begin removing the felt underbody panels. There are numerous small screws securing these panels.
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Note that the three rear screws on the front felt panel are different from the rest. Keep them organized to ensure correct reinstallation.
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When removing the side front ‘wings’, you’ll see the cable structure supporting the front felt panel. Slide the top sideways and then outwards to detach it. There’s no need to remove the two screws holding the bottom of these cables.
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Continue removing the remaining bottom felt pieces.
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More felt panel removal.
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With all felt pieces removed, you’ll be left with the undercarriage exposed. Note the clips at the bottom of the fan shroud that secure piping. Disconnect all pipes from these clips.
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Remove Aluminum Chassis Brace: The aluminum chassis brace needs to be removed. It is held by 7 bolts, one of which is located inside the front center jack support.
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Remove Transmission Felt Underbody Panel: Remove the felt underbody panel located beneath the transmission.
- Note any leaks, such as this DCT pan leak, which may need addressing during reassembly or as a separate repair.
3. Fan and Radiator Access:
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Fan Removal Preparation: Return to the top of the engine bay to address the fan assembly. While removing the airbox can simplify fan removal, it’s possible to remove it without further dismantling the intake system.
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Radiator Bolt and Connector: The radiator is secured by a single Torx bolt on the passenger side. Locate and remove this bolt.
- Disconnect the large electrical connector situated near the Torx bolt.
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Fan Clip and Removal: Attempting to slide the fan upwards will encounter resistance due to a clip on the driver’s side and pipes connected at the bottom. Focus on the driver’s side clip first.
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Reach down to the driver’s side edge of the fan assembly. Feel for the clip and unclip it while simultaneously lifting the fan upwards. This is a tight fit and may require some maneuvering and wiggling.
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Continue carefully wiggling and lifting the fan assembly until it is free.
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4. Steering Rack and Oil Drain:
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U-Pipe Removal: Return to the undercarriage. Locate a ‘U’ shaped pipe near the pipes previously disconnected from the fan. This pipe is bolted to the subframe.
- Remove the three bolts and one nut securing this U-pipe. Note that one of the three bolts is shorter and should be reinstalled on the passenger side of the steering rack.
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ABS/Brake Line Detachment: In the wheel wells, detach the ABS and brake lines from their strut connections to allow for subframe lowering.
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Drain Engine Oil: Prepare to drain the engine oil. Remember that the S65 engine has two drain plugs. Remove both to ensure complete oil drainage.
5. Sway Bar and Belt Tensioner:
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Sway Bar Link Disconnection: Disconnect the front sway bar links. BMW has improved the design from the E46 M3, allowing the use of two standard open-ended wrenches for removal.
