How to Replace Drive Belt Tensioner – DIY Guide
As a proud Mercedes-Benz owner, you know that keeping your vehicle in tip-top shape is a top priority. One crucial component that often gets overlooked is the drive belt tensioner. This unassuming piece plays a vital role in keeping your engine’s serpentine belt tensioned and preventing premature wear. And let’s be honest, replacing a belt is far cheaper than dealing with a snapped one on the highway. Buckle up, because today we’re tackling the drive belt tensioner replacement like a true DIY pro!
Key Takeaways:
- The drive belt tensioner ensures proper tension on the serpentine belt, preventing slippage and premature wear.
- Replacing the tensioner is a relatively straightforward task that can save you a visit to the mechanic (and a hefty bill).
- You’ll need a few basic tools, like a socket set, breaker bar, and a tensioner tool (around R500 – a worthwhile investment).
- Expect to spend around R1,200 – R2,000 on a genuine Mercedes-Benz drive belt tensioner for your model.
Identifying the Culprit
Before diving into the replacement process, you’ll want to make sure the drive belt tensioner is indeed the problem. Telltale signs include a squealing noise from the serpentine belt, visible cracks or damage on the tensioner pulley, and a loose or slipping belt. If you’ve already checked the serpentine belt itself and it’s in good condition, the tensioner is likely the root cause.
Gather Your Tools
Like any DIY project, having the right tools on hand is key. For this job, you’ll need:
| Tool | Purpose |
|---|---|
| Socket set (with appropriate size for tensioner bolt) | To loosen and tighten the tensioner bolt |
| Breaker bar (or long ratchet) | To provide extra leverage for loosening the tensioner bolt |
| Tensioner tool | To lock the tensioner in place while loosening and tightening the bolt |
| Basic hand tools (pliers, screwdrivers, etc.) | For any additional disassembly required to access the tensioner |
While you’re at it, grab a few rags or paper towels to catch any spills, and consider replacing the air filter while you’re under the hood.
Safely Remove the Old Drive Belt Tensioner
With the drive belt removed, you can now focus on the drive belt tensioner itself. First, locate the tensioner pulley and take note of how it is mounted. There will be either a bolt or a pin holding it in place.
If it’s a bolt, use the appropriate socket and ratchet to loosen and remove it. If it’s a pin, you may need a pin punch or drift to carefully knock it out. Be extremely careful not to damage any surrounding components.
Once the tensioner is free, you can remove it from the engine bay. Take a moment to inspect the old tensioner and compare it to the new one to ensure you got the correct replacement part.
Install the New Drive Belt Tensioner
Installing the new drive belt tensioner is essentially the reverse of the removal process. Slide the new tensioner into place and secure it with the bolt or pin, being careful not to overtighten.
Some tensioners have a specific way they need to be oriented, so consult your repair manual or online instructions for guidance.
| Step | Action |
|---|---|
| 1 | Locate the new drive belt tensioner and note its orientation |
| 2 | Slide the new tensioner into place in the engine bay |
| 3 | Secure the tensioner with the bolt or pin (do not overtighten) |
Reinstall the Drive Belt and Tension It Properly
With the new tensioner installed, you can now route the drive belt back onto the various pulleys and idlers in the correct order and orientation. Consult your repair manual if you’re unsure about the proper routing.
Once the belt is on, you’ll need to tension it correctly using the tensioner. This often involves using a pry bar or tensioning tool to rotate the tensioner and put the proper amount of tension on the belt.
Again, refer to your manual or online instructions for the specific tensioning procedure and specifications for your Mercedes model.
Comparison of Popular Drive Belt Tensioner Brands
When replacing the drive belt tensioner on your Mercedes, you’ll likely come across several different brand options. Here’s a quick comparison of some popular choices:
| Brand | Price Range | Quality | Availability |
|---|---|---|---|
| OEM (Mercedes-Benz) | R1200 – R2400 | Highest quality, exact fit | Dealers & some auto parts stores |
| Gates | R800 – R1600 | Very good quality | Most auto parts stores |
| Continental | R600 – R1400 | Good quality | Most auto parts stores |
| Aftermarket | R400 – R800 | Varying quality | Online retailers, some local stores |
While OEM Mercedes parts tend to be more expensive, they are guaranteed to be a perfect fit and meet the manufacturer’s specifications. Gates and Continental are well-respected brands that offer good quality at a slightly lower cost. Aftermarket tensioners can be very affordable but may sacrifice some quality or longevity.
FAQ
How often should I replace the drive belt tensioner?
Most manufacturers, including Mercedes-Benz, recommend replacing the drive belt tensioner whenever you replace the drive belts themselves, typically every 60,000 to 90,000 km or 4-6 years.
Can I replace just the tensioner or do I need a whole kit?
You can replace just the drive belt tensioner itself in many cases. However, Mercedes does offer some kits that include the tensioner along with new drive belts for convenience.
My tensioner seems stuck and won’t release tension. What should I do?
If the tensioner is seized or stuck, you may need to use a bit of penetrating oil or lubricant to help free it up. You can also try tapping on it gently with a rubber mallet. Avoid using excessive force to prevent damaging it further.
Do I need any special tools to replace the drive belt tensioner?
In most cases, you’ll only need basic hand tools like sockets, wrenches, and possibly a pry bar or tension tool. Consult your repair manual or Mercedes instructions to see if any special tools are required for your specific model.
What else should I inspect while replacing the drive belt tensioner?
Take the opportunity to inspect all drive belt components like the pulleys, idlers, water pump, and A/C compressor for signs of excessive wear or damage. You may want to replace other worn parts while you have everything disassembled. And don’t forget to check out our guide on how to change transmission fluid!
