5.9 Cummins Intercooler Boots: Which Kit Fits Your Ram?

A 5.9 Cummins can spend a lot of years hauling trailers, getting you to work and doing everything in between. When a charge-air boot finally needs attention, choosing its replacement should be straightforward.

For Mammoth’s 5.9L intercooler boot kits, start with two year ranges: 1994–2002 and 2003–2007. Both are listed for Dodge Ram 2500 and 3500 pickups with the 5.9L Cummins. If you’re buying radiator hoses at the same time, take one more look at the engine. The coolant kits use different application ranges, and 1998 deserves particular care.

Here’s how to work through it without buying parts twice.

Start with your year and engine

For a 1994–2002 Ram 2500 or 3500 with the 5.9L Cummins, start with the 1994–2002 intercooler boot kit. Its published fitment covers that full year range.

For a 2003–2007 Ram 2500 or 3500 with the 5.9L Cummins, choose the 2003–2007 intercooler boot kit.

Have a 2007? Check the engine before ordering. That model year includes both 5.9L and 6.7L trucks. The 5.9L kit is listed for the 5.9L engine; our 6.7 Cummins fitment guide covers the other application.

Use the truck’s model year together with its actual engine and plumbing. If it has an engine swap, aftermarket charge pipes or a different intercooler, the original vehicle details won’t tell the whole story. Compare what’s installed before choosing a factory-fit replacement.

What comes in the boot kits?

Both Mammoth 5.9 boot-kit pages list:

• Four five-ply silicone intercooler boots
• Eight stainless steel, spring-loaded constant-tension T-bolt clamps
• A maximum temperature rating of 350°F
• A pressure rating of over 100 PSI of boost
• Black, blue and red options

The boots replace the flexible charge-air connections. Metal pipes and the intercooler itself aren’t included.

Those specifications help you compare kits, but the right shape and application still come first. A pressure rating also isn’t a pressure-test instruction. Follow the appropriate vehicle and tester procedure when checking a charge-air system.

Adding radiator hoses? Check the application separately

Intercooler boots and radiator hoses do different jobs. The boots connect the pressurized intake-air system; radiator hoses carry engine coolant. Sharing a truck’s model year doesn’t mean the two kits use identical fitment splits.

For 1994–1997 trucks, Mammoth lists an upper and lower radiator hose kit.

For 1998.5–2002 24-valve trucks, the 24-valve radiator hose kit specifically excludes the 12-valve engine.

If you own a 1998, identify the engine before choosing coolant hoses. Don’t assume that a model-year label alone settles whether the truck has a 12-valve or 24-valve setup. Check the actual engine and hose connections, particularly if its history is unknown. Ask about the correct coolant kit if there’s any uncertainty.

For 2003–2007 5.9L trucks, Mammoth lists the 2003–2010 radiator hose kit. Its broader application includes certain 6.7L trucks, but the product page restricts 2010 fitment to the older body style. That exception matters if you’re also shopping for another truck.

Mammoth also offers combined boot-and-radiator-hose kits. Check each combo’s application and contents rather than assuming its year range matches the boots-only kit. Browse the Cummins coolant hose range to compare the options.

Find the problem before replacing the parts

A hiss under load or a change in performance is a reason to inspect the charge-air system. It doesn’t identify a failed boot by itself. A loose connection, damaged pipe or leaking intercooler can also need attention.

With the engine off and cool, look over the boots, clamps and nearby pipes. Check for visible damage, rubbing and connections that have moved. If testing is needed, follow the correct service procedure or have a qualified shop locate the leak. Our boost-leak guide is a useful place to start.

If one boot is damaged, inspect the others while you’re there. Their condition can help you decide how much work the truck needs without assuming every hose must be replaced.

A little preparation makes installation easier

Before removing anything, take a few photos of the existing routing and compare the new boots with the connections they’ll replace. If a pipe is bent or the plumbing has been modified, stop and resolve the mismatch before tightening everything down.

Use the correct clamp specification for the components you’re installing. If you don’t have that information, ask before guessing. After installation, check the system using the appropriate service procedure before putting the truck back under a heavy load.

Ready to choose your kit?

Start with the 1994–2002 or 2003–2007 boot-kit application, confirm the truck has the 5.9L Cummins, and check radiator-hose fitment separately if you need both.

For a modified truck, a 1998 coolant-hose question or an application outside the published fitment, contact Mammoth before ordering. Include the year, engine and clear photos of the connections you’re working with. It’s easier to sort out those details before the truck is apart.