How to Route the Serpentine Belt on a 2010 Ram 1500 Without Losing Your Mind
The serpentine belt on these trucks is one of those things that looks simple until you're on the ground and it won't go back on. The 2010 Dodge Ram 1500 came with three engine options — the 4.7L V8, the 5.7L Hemi V8, and the 6.7L Cummins diesel — and each one has a different belt path. Most people searching for the 2010 Dodge Ram 1500 Serpentine Belt Diagram are dealing with the 5.7L Hemi, so I'll focus there, but I'll note the differences for the other engines. Before we get into routing, here's the basic layout for the 5.7L: the belt wraps around the crankshaft pulley at the bottom, goes up to the power steering pump on the left side, then to the idler pulley above that, over the A/C compressor, down to the alternator, and back to the tensioner pulley on the right side before looping back to the crank. That's the standard path. The tensioner is the spring-loaded pulley that gives you the slack you need to stretch the belt over or off any of the stationary pulleys.
2010 Dodge Ram 1500 Serpentine Belt Diagram by Engine
5.7L Hemi V8 (engine code RII): Starting at the crank pulley, the belt routes clockwise around the crank, up the driver's side to the power steering pump, then to the upper idler pulley, around the A/C compressor, down to the alternator, around the tensioner pulley, and back to the crank. The A/C compressor pulley is the one that catches people out — the belt rides on the inner groove, not the outer face. 4.7L V8: Similar layout but the A/C compressor sits in a slightly different position, and there's no water pump in the belt loop on this engine since the 4.7L uses an internal cooling loop for the water pump drive. If your belt keeps popping off near the A/C compressor, that's a strong sign it's actually a 4.7L and someone has tried to route a Hemi diagram belt on it — the pulley spacing is just wrong. 6.7L Cummins diesel: Completely different setup. The diesel has a much longer belt path, additional idler pulleys, and the tensioner is positioned differently. If you've got the diesel, don't use any of the V8 diagrams — the belt won't even reach the right pulleys.
I spent about twenty minutes last fall trying to put a belt back on a customer's 5.7L after a shop had replaced the power steering pump. They'd gotten it mostly right but had the belt routed around the outside of the A/C compressor instead of through the grooved pulley. It looked close enough from the top of the engine bay that nobody caught it until the belt started squealing after ten minutes of operation. The fix was simple — relieve tension, pop it off, and reseat it in the correct groove. But it was a good reminder that these diagrams are only useful if you actually trace the path before you start. Here's the practical procedure. You'll need a 3/8-drive ratchet with a 15mm socket or a belt tensioner tool, depending on how space-constrained you're working. The tensioner bolt is a 15mm, and you're pushing the tensioner clockwise to relieve pressure on the belt. I've seen people try to use an extension bar at a awkward angle and strip the bolt head. Don't do that. Get a proper breaker bar or a long ratchet handle so you can apply steady, even force without slipping. Remove the old belt first. Take a photo with your phone before you pull it off. Seriously. I know it sounds obvious, but in the sunlight under a truck with eight pulleys going on, the belt looks identical no matter how it's routed, and you'll thank yourself later. Once the old belt is off, clean the pulleys. I mean actually clean them. These trucks sit in places where belt debris, oil spray from the valve cover gaskets, and road grime build up on the pulley faces. A quick wipe with brake cleaner and a rag makes the new belt last significantly longer and reduces the chance of premature slipping.
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Now route the new belt following your diagram. Start with the crank pulley, then work your way around the stationary pulleys first, leaving the last one — usually the tensioner — for last. The belt should sit flush in every pulley groove. If it's riding on the edge of a pulley, you've got it wrong, and forcing it will just make it jump off again once you release the tensioner. Apply tension to the tensioner pulley with your tool, slide the belt over the final pulley, and slowly release the tensioner. Double-check every groove before you start the engine. Listen for any chirping or squealing on the first startup — that's usually a sign the belt isn't fully seated in one of the pulleys, or you've got a bad tensioner bearing. A couple of things most guides don't mention. The tensioner on these Rams tends to fail around 80,000 to 100,000 miles, and when it does, it doesn't always announce itself with a noise. Sometimes it just loses enough tension that the belt slips under load — you'll notice the power steering getting heavy at idle or the battery light flickering. If your new belt keeps slipping within a few thousand miles, replace the tensioner before you replace the belt again. Second, if you're dealing with the 5.7L and the A/C isn't engaging properly after a belt change, check that the belt is actually driving the A/C compressor pulley. I've seen aftermarket belts that were slightly too short or from a different manufacturer's spec sheet, and they'd route correctly but not engage the compressor fully because the pulley depth was off by a fraction of an inch.
For finding the actual diagram, Mopar's official service documentation is the most accurate source, but the free Chilton or Haynes diagrams online are generally correct for the 5.7L. Just verify your engine code first — it's stamped on a plate near the radiator support on the driver's side. The 6.7L Cummins owners, especially, should double-check because so many online diagrams conflate the V8 and diesel layouts. If you want a direct image file, the Ram Forum has a pinned thread with a high-res diagram that's been verified against factory service manuals. No need to pay for a subscription — just scroll to the first post. The whole job should take you about 20 to 30 minutes if you've done it before and have the right tools. First time, give yourself an hour and keep that phone handy for a reference photo. The belt costs roughly $35 to $65 depending on brand — Gates and Michelin are the ones I trust on these. Skip the cheap no-name belts; they don't last and they're harder to route because the tolerances are looser.
