DIY Guide to Mercedes-Benz 560 Timing Chain Guide Replacement

For Mercedes-Benz 560 owners and DIY enthusiasts considering tackling timing chain guide replacement, this guide provides a detailed walkthrough. It’s crucial to understand upfront that while DIY is possible, this task demands a solid foundation in automotive repair. Lack of experience can lead to costly mistakes. This article will help you navigate the process, emphasizing key steps and precautions for a successful timing chain guide replacement on your Benz 560.

Understanding Timing Chain Guides and Why Replacement is Necessary

Timing chain guides are critical components within your Mercedes-Benz 560 engine. These guides, typically made of nylon or similar materials, ensure the smooth and proper operation of the timing chain. Over time and with heat cycles, these guides can become brittle and fracture.

A fractured timing chain guide, like the one shown below, poses a significant risk. If pieces of the guide fall into the path of the timing chain, it can lead to catastrophic engine damage, often resulting in bent valves and requiring extensive repairs.

Image: A close-up view of a fractured timing chain guide removed from a Mercedes Benz 560 engine, highlighting the point of failure and potential for engine damage.

Beyond the easily accessible cylinder head guides, the Mercedes 560 engine also has lower timing chain guides and an oil pump chain guide, located behind the timing cover. Accessing these lower guides is significantly more labor-intensive, often requiring engine removal or at least cylinder head removal. While these lower guides are generally less prone to failure than the upper ones, their condition should be considered during major engine work. For many DIY repairs, focusing on the upper cylinder head guides and tensioner guide is a common approach to address preventative maintenance.

When undertaking this repair, using only Original Equipment (OE) Mercedes-Benz parts or parts specifically approved for Mercedes-Benz vehicles is highly recommended to ensure quality and compatibility.

This guide focuses on the Mercedes Benz 560, specifically the 560 SL model from 1989, but the procedure is largely applicable to other 560 models with minor variations in engine attachments. While some photos may show the intake manifold removed for clarity, its removal is generally not necessary for timing chain guide replacement itself, unless addressing other maintenance tasks simultaneously.

Tools and Parts Needed for Benz 560 Timing Chain Guide Replacement

Before starting the timing chain guide replacement on your Mercedes 560, ensure you have the following tools and parts:

• New Timing Chain Guides (OE Mercedes-Benz recommended): Specifically for the upper cylinder heads and tensioner.
• New Timing Chain Tensioner (OE Mercedes-Benz recommended): Consider replacing the tensioner at the same time.
• New Timing Chain (OE Mercedes-Benz recommended): Often recommended as part of a complete timing chain service.
• Valve Cover Gaskets: Likely need replacement after removing valve covers.
• Assorted Sockets and Wrenches: Metric sizes appropriate for Mercedes-Benz engines.
• Impact Wrench: For loosening camshaft sprocket bolts.
• Torque Wrench: For proper bolt tightening during reassembly.
• Camshaft Holding Tool (Channel Locks or similar): To secure camshafts while loosening bolts.
• Pin Puller Tool (or DIY alternative): For removing guide pins (a valve cover bolt, socket, and washers can be fashioned as a puller).
• Wooden Hammer Handle or Soft Mallet: For tapping components gently.
• Wire: For securing the timing chain to prevent it from falling into the engine.
• Sealant: For timing guide pin installation.
• Tie-wraps (Optional): To secure the chain to sprockets during removal.
• Penetrating Oil: To help loosen bolts.
• Shop Rags and Cleaning Supplies: For general cleanup.

Step-by-Step Guide to Replacing Benz 560 Timing Chain Guides

This section provides a step-by-step guide to replacing the upper timing chain guides on a Mercedes-Benz 560.

Preparation and Timing Alignment

1. Prepare the Vehicle: Disconnect the negative battery terminal for safety.

2. Remove Components: Remove the valve covers, power steering pump and bracket (can often be set aside), and alternator and bracket (also often can be set aside).

   Image: A Mercedes Benz 560 engine bay with the valve cover and some accessory components like the power steering pump and alternator partially removed, setting the stage for timing chain guide access.

3. Align Timing Marks – Driver’s Side Camshaft: Rotate the engine clockwise until the timing marks on the driver’s side camshaft are aligned. These are usually small marks in the center of the camshaft gears.

   Image: Close-up view of the driver’s side camshaft on a Mercedes Benz 560 engine, showing the timing marks precisely aligned for accurate timing reference.

4. Align Timing Marks – Passenger’s Side Camshaft: Verify the timing marks on the passenger’s side camshaft are also aligned.

   Image: Detailed view of the passenger’s side camshaft of a Mercedes Benz 560 engine, confirming the correct alignment of timing marks mirroring the driver’s side.

5. Set Engine to TDC (Top Dead Center): Continue rotating the engine until it reaches Top Dead Center (TDC). This is indicated by the crankshaft pulley mark aligning with the “0” mark on the engine block. Also, check that the ignition distributor rotor is pointing to the #1 cylinder position.

   Image: Mercedes Benz 560 engine positioned at Top Dead Center (TDC), with a clear view of the aligned timing marks on the crankshaft pulley and distributor rotor pointing to cylinder #1.

Accessing the Timing Chain Guides

6. Secure Camshaft and Mark Position – Driver’s Side: Use tie-wraps (optional but helpful) to secure the timing chain to the camshaft sprocket. Mark the position of the camshaft sprocket relative to the timing chain and camshaft itself for reassembly reference.

   Image: The driver’s side camshaft area of a Mercedes Benz 560 engine, showing the camshaft marked for position and secured with tie-wraps to the timing chain before sprocket removal.

7. Crankshaft Timing Mark Check: Reconfirm the crankshaft timing mark is still pointing to the zero position.

   Image: Detailed view of the crankshaft pulley on a Mercedes Benz 560 engine, clearly showing the timing mark aligned at the zero position, crucial for correct engine timing.

8. Loosen Camshaft Sprocket Bolt – Driver’s Side: Use an impact wrench to briefly loosen the camshaft sprocket bolt on the driver’s side. Simultaneously, use channel locks or a similar tool to hold the camshaft steady using the nubs in the center, being careful not to damage the camshaft oiling tube and its plastic clips. Once loosened, unthread the bolt by hand and set it aside.

   Image: Action shot of an impact wrench being used to loosen the camshaft sprocket bolt on a Mercedes Benz 560 engine, with a camshaft holding tool ensuring stability during the process.

9. Suspend Timing Chain: Attach a wire from the hood down to the camshaft sprocket area. Create a loop to suspend the timing chain, ensuring it remains taut and does not fall into the engine.

10. Remove Camshaft Sprocket – Driver’s Side: Gently tap the backside of the sprocket with the wooden end of a hammer handle (never use metal directly). Wiggle and pull the sprocket towards you, being mindful of the timing chain.

    Image: The camshaft sprocket being carefully removed from a Mercedes Benz 560 engine, while the timing chain is held taut to prevent it from slipping or falling into the engine cavity.

Removing the Old Guides

11. Retain Washer: Be careful not to drop the washer behind the camshaft sprocket into the engine. It’s crucial to retrieve it if it comes loose.

Image: Close-up view highlighting the washer located behind the camshaft sprocket on a Mercedes Benz 560 engine, emphasizing the need for caution to prevent it from falling into the engine.

12. Reinstall Bolt (Hand-Tight): Reinstall the camshaft sprocket bolt hand-tight to retain the sprocket and washer, preventing them from falling.

Image: The camshaft sprocket bolt reinstalled by hand on a Mercedes Benz 560 engine, securing the sprocket and washer in place temporarily.

13. Remove Guide Pins: Use a pin puller tool (or your DIY version) to carefully extract the pins holding the timing chain guides. Be extremely cautious not to strip the threads or bend the pins. If using a DIY puller, ensure even pressure and clearance for pin removal.

Image: A DIY pin puller tool in action, removing a guide pin from the timing chain guide on a Mercedes Benz 560 engine, requiring careful and controlled extraction.

14. Pin Removed: Once the pin is pulled sufficiently, you should be able to remove it by hand.

Image: The guide pin shown partially extracted from the timing chain guide on a Mercedes Benz 560 engine, indicating successful removal using the puller tool.

15. Remove Last Pin and Guide: Remove the final pin holding the guide, and carefully remove the old timing chain guide, ensuring it does not fall into the engine.

Image: Focus on the last pin being removed from the timing chain guide on a Mercedes Benz 560 engine, critical for releasing the guide for replacement.

16. Old vs. New Guide Comparison: Compare the old, brittle guide with the new Mercedes-Benz replacement guide. Notice the difference in material flexibility.

Image: A side-by-side comparison of an old, worn timing chain guide next to a brand new Mercedes-Benz replacement guide, highlighting the material difference and wear.

Installing New Guides

17. Install New Guide: Slide the new timing chain guide into position, aligning the holes for the pins. You may need to lightly tap the guide to seat it correctly.

Image: The new timing chain guide being installed onto a Mercedes Benz 560 engine, precisely aligned and ready for pin insertion.

18. Install Pins: Push the pins through the new guide and into their bores. Ensure they are seated properly.

19. Apply Sealant: Apply a small amount of sealant to the ends of the pins to prevent oil seepage.

Reassembly and Final Checks

20. Reinstall Camshaft Sprocket: Reinstall the camshaft sprocket, aligning it with your previously made marks on the chain and camshaft. Tighten the camshaft sprocket bolt to the correct torque specification using a torque wrench, while again holding the camshaft steady.
21. Repeat for Other Side: Repeat steps 6-19 for the other side of the engine.
22. Reinstall Remaining Components: Reinstall the valve covers with new gaskets, power steering pump, alternator, and any other components removed.
23. Reconnect Battery: Reconnect the negative battery terminal.
24. Start Engine and Check: Start the engine and listen for any unusual noises. Check for leaks.
25. Verify Timing: Double-check the engine timing to ensure it is correct.

Important Considerations and Warnings

• Experience Level: This DIY task is best suited for individuals with significant automotive repair experience.
• OE Parts: Using genuine OE Mercedes-Benz parts is highly recommended for reliability and longevity.
• Engine Damage: Improper procedure can lead to serious engine damage, including bent valves.
• Seek Professional Help: If you are unsure about any step, it is always best to consult a qualified Mercedes-Benz mechanic.
• Lower Guides: Remember that this guide focuses on the upper guides. Lower guide replacement is a more complex task.

Replacing the timing chain guides on your Mercedes-Benz 560 is a significant undertaking. By following these steps carefully and adhering to safety precautions, you can potentially complete this repair yourself. However, always prioritize safety and seek professional help when needed. For more Mercedes-Benz DIY guides and parts, visit benzxentry.store.

Disclaimer: This guide is for informational purposes only and should not be considered a substitute for professional mechanical advice. Always consult your vehicle’s repair manual and take necessary safety precautions.