Accessory Drive Belt Guide for the E34 (1995) & E39 (1999) BMW M5
Understanding the critical accessory drive belts is key to maintaining your M5's legendary performance and reliability.
- The 1995 (E34) and 1999 (E39) M5 are different generations; verify your car before buying parts.
- For the E39 M5, watch for oil leaks from the oil filter housing, as they can destroy the belts and lead to catastrophic engine failure.
- Always replace belt tensioners and idler pulleys with the belts to prevent premature failure of the new belt.
- Continental is the OEM supplier, offering dealer-level quality without the high price tag.
A Tale of Two M5s: 1995 vs. 1999
Before buying parts, it's critical to understand that the "1995-1999 BMW M5" covers two completely different generations. The parts are not interchangeable.
- 1995 BMW M5 (E34): This was the final year for the E34 generation, which was primarily sold in Europe by this time. It uses the S38 inline-six engine with a multi-V-belt system for its accessories.
- 1999 BMW M5 (E39): This was the debut year for the E39 M5 in North America. It features the powerful S62 V8 engine, which uses a serpentine belt system with two separate belts.
This guide will cover the specifics for both models. Always confirm your vehicle's model year and generation before ordering.
Symptoms of a Failing Accessory Drive Belt
A failing belt provides clear warning signs. Ignoring them can lead to a sudden breakdown and potential engine damage from overheating.
- Squealing or Chirping Noises: This is the most common symptom, especially on cold starts or during wet weather. The noise comes from the belt slipping on the pulleys.
- Visible Wear and Damage: A visual inspection is key. Look for cracks, fraying, glazing (a shiny surface), or missing pieces of the belt's ribs.
- Accessory Failure: If your power steering becomes heavy, the battery warning light illuminates, or the engine temperature gauge rises quickly, your main belt may have failed.
- Rattling or Grinding Sounds: These noises often point to failing tensioners or idler pulleys. A bad pulley can quickly shred a brand-new belt, so it's crucial to inspect them during replacement.
Critical Warning for E39 M5 (S62 V8) Owners
A common issue on the S62 engine is an oil leak from the oil filter housing gasket. This leak can drip directly onto the accessory belts. Oil contamination will cause the rubber to swell, soften, and slip off the pulleys. In a worst-case scenario, the derailed belt can be pulled past the front crankshaft seal into the engine, causing catastrophic internal damage. Address any oil leaks immediately to prevent this costly failure.
Choosing the Right Aftermarket Belt
You don't need to buy a "Genuine BMW" part to get the best quality. Understanding the manufacturers is key.
- Top Tier (OEM Supplier): Continental (also branded as ContiTech) is the Original Equipment Manufacturer (OEM) for BMW's drive belts. Choosing a Continental belt gives you the exact same quality as the dealer part, just without the BMW logo and price markup. This is the recommended choice for most owners.
- High-Quality Aftermarket: Brands like Gates are also highly respected in the automotive community and offer excellent performance and reliability. Bando and Dayco are other solid options.
- Performance: Some brands offer belts reinforced with materials like Kevlar. These are an option for aesthetics or heavily modified cars but are not necessary for most applications.
Pro Tip: Replace More Than Just the Belt
The belt tensioners and idler pulleys wear out over time. A seized pulley can destroy a new belt and leave you stranded. It is strongly recommended to replace the belts, tensioners, and idler pulleys as a complete kit for peace of mind.
Accessory Drive Belt Cost Comparison
| Part Type | Price Range | Notes |
|---|---|---|
| New OEM (Genuine BMW) | $60 - $115 | Highest cost, identical to OEM supplier part. |
| New Aftermarket (OEM Supplier) | $25 - $50 | Best value. Continental is the OEM supplier. |
| Shop Labor | $100 - $330 | Typically 1-2 hours of work. |
| Total Professional Replacement | $150 - $500+ | Cost varies by shop and if tensioners/pulleys are replaced. |
Frequently Asked Questions (FAQ)
How often should I replace the accessory belts?
As a general rule, inspect the belts at every oil change and plan to replace them every 4 years or 50,000 miles, or sooner if you see any signs of wear. Given the critical nature of these parts on an M5, preventative replacement is wise.
Do I really need to replace the tensioners and pulleys too?
Yes, it is highly recommended. The bearings in these pulleys do not last forever. A failed pulley can cause the new belt to fail, potentially leading to engine overheating. Replacing them with the belt is cheap insurance.
What are the belt part numbers for my M5?
Always verify with your VIN, but common part numbers are:
- E39 M5 (S62 V8): Main Accessory Belt: 7PK1629 (BMW PN: 11287833264). A/C Belt: 5PK905.
- E34 M5 (S38 I6): This model uses multiple V-belts. Common sizes include 13x980mm for the alternator (BMW PN: 11231315357) and 13x968mm for the A/C compressor.
Can I drive my M5 if the accessory belt is broken?
No. If the main accessory belt fails, the water pump will stop spinning, and the engine will overheat very quickly, leading to severe and expensive damage. You will also lose power steering and the alternator will no longer charge the battery. Pull over safely and shut off the engine immediately.
Technical Specifications
OEM Part Numbers: 11287833264 (E39 M5 Main Belt) 11231315357 (E34 M5 Alternator Belt)
E39 M5 S62 V8: Uses a main serpentine belt (7PK1629) and a separate A/C belt. E34 M5 S38 I6: Uses a multiple V-belt system.
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- BMW M5: