The belt diagram is typically printed in the engine bay on a sticker (often under the hood or on the radiator/core support) or included with the vehicle’s owner’s or service manual. If it isn’t visible there, you can often find a VIN-specific diagram through official manufacturer portals or reputable repair manuals.
Common places to look in the engine bay
These locations are the most frequent spots where a vehicle will display the belt routing diagram for serpentine or V-belts.
- Under the hood on a decal near the edge of the engine bay, often on the underside of the hood itself
- On the radiator core support or a nearby framing member in the engine bay
- Inside the engine cover or a removable timing/belt cover, sometimes printed on the cover itself
- In the vehicle’s owner’s manual or the official service manual (print or PDF)
- Through manufacturer VIN-based service portals or dealer service bulletins
If you still can’t locate a diagram after checking these spots, consult the dealership or a trusted repair manual, and avoid making belt changes without a confirmed diagram.
How to read and use the belt diagram
Understanding the diagram helps you route or re-route a belt correctly when replacing it or performing maintenance.
- Trace the belt path around all pulleys as shown, noting the direction and which pulleys are driven
- Check the belt’s orientation (ribbed side versus smooth side) as indicated by the diagram
- Verify the position of the tensioner and idler pulleys and ensure the belt sits correctly in all grooves
- Cross-check the diagram with the actual belt arrangement before removal or reinstallation
- Take a photo or make a quick sketch of the current routing before taking the belt off to aid reassembly
Where to find online and printed resources
If a physical diagram isn’t accessible in your car, these sources can provide reliable guidance or VIN-specific diagrams.
- Vehicle owner’s manual (PDF or printed) for basic belt routing information
- Official manufacturer service portals or dealer portals that offer diagrams by VIN
- Professional repair manuals such as Haynes or Chilton
- Comprehensive repair databases like Alldata or Mitchell1 (often subscription-based)
- Auto parts retailer sites (AutoZone, O’Reilly, etc.) that host belt diagrams for many models
- Video tutorials and model-specific walk-throughs on YouTube or automotive forums
When using online resources, ensure the diagram matches your exact model, year, and engine variant, since belt routing can vary between configurations of the same model.
Summary
In most vehicles, the engine belt diagram is found on an engine-bay decal (often under the hood or on the radiator support) or in the owner’s/service manual. If it isn’t visible, check manufacturer portals or repair manuals for VIN-specific diagrams, and consult reputable online resources or trained technicians if you’re unsure. A correct diagram is essential for proper belt installation and system function.
How long can I drive with a bad drive belt?
Technically, the engine may keep running for a short time if the battery has enough charge, and if the water pump runs on a separate drive. But driving without a serpentine belt is never safe, and it doesn't take long before other systems shut down.
Are engine belts easy to replace?
It takes maybe a minute. If the belt snaps, replacing it is trivial. You just need to pass the new belt around the fan, loosen the alternator's tensioning bolt, put the new belt on the crank, water pump and alternator pulleys, and tension it.
How much is a drive belt for a Mazda 3?
The cost of having a Mazda drive belt/s replaced varies between $100 - $400+ depending on the style of drive belt/s and if other engine components need to be removed to allow access to replace it. Sometimes you will get a noise warning when the drive belt tension has changed and it needs to be replaced or refitted.
Where is the belt diagram?
Look under the hood.
All vehicles come from the factory with the belt routing for that specific make and model under the hood. The diagram will show which pulleys each belt goes on and how to route the belt.