Replacing the timing chain guides on a Mercedes Benz 560 can seem like a daunting task, but for experienced mechanics, it’s a manageable DIY project. However, it’s crucial to understand that this job is not for beginners. Incorrect procedures can lead to significant engine damage and costly repairs. This guide outlines the process of replacing these critical components, focusing on the Mercedes Benz 560 model.
Before diving in, it’s essential to recognize the importance of timing chain guides. These guides ensure the timing chain runs smoothly and accurately, which is vital for proper engine function. A fractured timing chain guide, a common issue in older Mercedes Benz 560 models, can cause serious engine problems, including bent valves and engine damage.
Image: A close-up view of a broken timing chain guide removed from a Mercedes Benz 560 engine, highlighting the fracture point.
As shown in the image above, a broken guide can have severe consequences. When a guide fractures and pieces fall into the timing chain path, it can cause timing misalignment and potentially catastrophic engine failure. While this guide focuses on the upper timing chain guides, it’s worth noting that Mercedes Benz 560 engines also have lower guides for the oil pump chain. Due to their location and the extensive labor required to access them, these lower guides are often addressed during a complete engine overhaul. However, the upper guides are known to be more prone to failure and are the primary focus of this repair.
For many Mercedes Benz 560 owners, replacing the upper cylinder head guides, the tensioner guide, the tensioner itself, and the timing chain is a common preventative maintenance procedure. For this critical Mercedes Benz 560 repair, using only Original Equipment (OE) Mercedes-Benz parts or parts specifically approved for Mercedes-Benz vehicles is highly recommended to ensure reliability and longevity.
This guide is based on a 1989 Mercedes Benz 560 SL, but the process is similar for most Mercedes Benz 560 models, with minor variations depending on engine attachments. While the intake manifold is shown removed in some images for clarity, it’s generally not necessary to remove it for this specific timing chain guide replacement procedure on a Mercedes Benz 560. The following steps assume you have already removed the valve covers, power steering pump, and alternator (and their respective brackets). The power steering pump and alternator can often be moved aside without complete removal.
Step-by-Step Guide to Mercedes Benz 560 Timing Chain Guide Replacement
1. Aligning Timing Marks:
Begin by rotating the engine to align the timing marks. On the driver’s side camshaft, locate the small marks in the center of the camshaft and align them as shown.
Image: Detailed view of the driver’s side camshaft on a Mercedes Benz 560, showing the timing marks aligned for accurate guide replacement.
2. Passenger Side Timing Marks:
Similarly, check and align the timing marks on the passenger side camshaft of your Mercedes Benz 560 engine.
Image: Clear depiction of the passenger side camshaft of a Mercedes Benz 560, with timing marks correctly aligned for the procedure.
3. Setting to Top Dead Center (TDC):
Ensure the engine is set to Top Dead Center (TDC). Tie-wraps can be helpful to secure the chain and sprocket, especially when working alone, and during camshaft bolt removal.
Image: The Mercedes Benz 560 engine positioned at TDC, with tie-wraps used to secure the timing chain to prevent slippage during component removal.
4. Securing the Driver’s Side Camshaft:
Mark and secure the driver’s side camshaft before removing the camshaft sprocket bolt. This prevents unwanted camshaft rotation.
Image: Close-up of the driver’s side camshaft on a Mercedes Benz 560, showing it marked and secured in place before bolt removal.
5. Crankshaft Timing Marks:
Verify the crankshaft timing mark is pointing to the Zero position. Also, confirm the ignition distributor rotor is pointing to the #1 cylinder position. These checks are crucial for correct timing.
Image: View of the crankshaft pulley on a Mercedes Benz 560, clearly showing the timing mark aligned at the zero position.
6. Loosening the Camshaft Bolt:
Using an impact wrench, carefully loosen the camshaft bolt. Secure the camshaft with channel locks, being mindful of the camshaft oiling tube and its fragile plastic clips. Once loosened, the bolt should unscrew by hand.
Image: Mechanics using an impact wrench to loosen the camshaft bolt on a Mercedes Benz 560, with channel locks securing the camshaft.
7. Removing the Camshaft Sprocket:
After removing the bolt, run a wire to suspend the timing chain from the hood. Gently tap the backside of the sprocket with the wooden end of a hammer to remove it. Avoid using the steel part of a hammer or a rubber mallet, as they can cause damage or leave debris. Wiggle and pull the sprocket towards you, being careful with the timing chain.
Image: Removal of the camshaft sprocket on a Mercedes Benz 560, with the timing chain being carefully held to prevent it from falling into the engine.
8. Washer Removal:
Be cautious of the washer behind the sprocket, as it can easily fall into the engine. Reinstall the camshaft bolt temporarily to prevent the washer from dropping.
Image: Close-up highlighting the washer behind the camshaft sprocket on a Mercedes Benz 560, emphasizing the need to prevent it from falling into the engine.
9. Bolt Re-installation:
Hand-tighten the bolt to secure the sprocket washer and timing mark in place.
Image: The camshaft bolt hand-tightened on a Mercedes Benz 560, securing the sprocket washer and maintaining the timing mark position.
10. Removing the Old Guides:
Pulling the old guides requires care. Specialized tools are available, but a DIY puller can be fashioned using valve cover bolts, sockets, and washers. When using a DIY puller or removing pins, be extremely careful not to strip or bend the pins.
Image: Using a pin puller tool to remove the pins holding the timing chain guide on a Mercedes Benz 560 engine.
11. Pin Removal:
Once the pin is partially pulled, it should be removable by hand.
Image: A timing chain guide pin on a Mercedes Benz 560 engine, shown partially removed and ready for manual extraction.
12. Final Pin Removal and Guide Extraction:
The last pin secures the guide. Hold the guide to prevent it from falling into the engine once this pin is removed.
Image: The final pin being extracted from the timing chain guide on a Mercedes Benz 560 engine, with the guide being held in place.
13. Old vs. New Guide Comparison:
Compare the old, brittle guide with the new Mercedes-Benz replacement guide. The difference in material condition will be noticeable.
Image: A side-by-side comparison highlighting the visual difference between an old, worn timing chain guide and a new, genuine Mercedes Benz 560 replacement part.
14. Installing New Guides:
Slide the new guide into place and push the pins through, aligning the holes. Lightly tap the pins if needed, and apply sealant to the ends to prevent oil seepage.
Image: Installation of the new timing chain guide onto a Mercedes Benz 560 engine, with pins being inserted to secure it.
15. Sealant Application:
Apply sealant to the pin ends to prevent oil leaks.
Image: Close-up of sealant being applied to the ends of the timing chain guide pins on a Mercedes Benz 560 engine to prevent oil seepage.
Conclusion:
Replacing the timing chain guides on your Mercedes Benz 560 is a critical maintenance task that, while DIY-able for experienced mechanics, demands precision and caution. By following these steps and using OE Mercedes-Benz parts, you can ensure the longevity and reliability of your engine. Remember to double-check all timing marks and secure components properly during reassembly. If you are unsure about any step in this process, it is always best to consult a professional Mercedes-Benz mechanic.
