What Comes in the Kit?
The MMHOSE-RAM-03DE kit includes:
- One upper radiator hose
- One lower radiator hose
- High-quality worm-gear clamps
This kit replaces the two primary radiator hoses. It does not include heater hoses, turbocharger coolant lines, the 6.7L upper heater-hose assembly, thermostat, radiator cap or water pump.
OEM-Style EPDM Construction
EPDM is commonly used for original-equipment coolant hoses because it resists heat, coolant exposure, ozone and long-term environmental degradation. Mishimoto designed this replacement kit to retain factory-style routing and appearance.
EPDM is a strong choice for:
- Work trucks
- Tow vehicles
- Daily-driven Cummins pickups
- Stock restorations
- Fleet maintenance
- Owners who prefer factory-style replacement parts
This is not Mishimoto’s silicone performance-hose kit. Buyers specifically looking for a higher-temperature silicone construction should choose the corresponding MMHOSE-RAM-03D silicone kit in the appropriate color.
Why Replace Aging Cummins Radiator Hoses?
Radiator hoses experience temperature changes, cooling-system pressure, engine vibration and exposure to oil or road contaminants. Diesel trucks used for towing or hauling place additional thermal demand on the cooling system.
Inspect or replace the hoses if you notice:
- Cracks near either connection
- Bulges or swollen sections
- Soft or spongy rubber
- Hardened hose ends
- Coolant residue near the clamps
- Abrasion against nearby components
- Coolant dripping beneath the truck
- A sweet smell after driving
- Unexplained coolant loss
- Engine-temperature increases under load
- Lower-hose collapse
A hose can deteriorate internally while appearing acceptable from the outside. If coolant is disappearing without leaving a convenient puddle, use our guide on how to find a coolant leak to inspect the system under the correct conditions.
Designed for Work, Towing and Daily Driving
The Cummins engine generates substantial heat while towing, climbing grades or operating under sustained load. A leaking or restricted hose can reduce coolant circulation and lead to rapid temperature increases.
Fresh radiator hoses help maintain a sealed coolant path between the engine and radiator. However, they cannot compensate for:
- A clogged radiator
- Damaged cooling fan
- Weak fan clutch
- Failed thermostat
- Worn water pump
- Incorrect coolant mixture
- Trapped air
- Combustion leakage
- Restricted airflow
A cooling system is a team effort. One fresh hose cannot carry the entire roster while the radiator is packed with seventeen years of bugs and bad decisions.
Installation Notes
Never remove the pressure cap or disconnect a cooling-system hose while the engine is hot. Diesel cooling systems can remain pressurized after shutdown and release dangerously hot coolant.
Typical installation involves:
- Allowing the engine to cool completely.
- Disconnecting the negative battery cables where required.
- Draining the coolant into a suitable container.
- Recording the original hose routing.
- Removing the factory clamps and hoses.
- Cleaning the radiator and engine-side connections.
- Comparing the new hoses with the originals.
- Installing the hoses without twisting or kinking them.
- Positioning the clamps behind each connection bead.
- Refilling with the correct coolant.
- Bleeding trapped air according to factory procedures.
- Bringing the engine to operating temperature.
- Inspecting each connection for leakage.
Keep the hoses away from belts, pulleys, fan blades and sharp brackets. Follow Mishimoto’s instructions for clamp placement and tightening specifications.
If the coolant is old, contaminated or of unknown specification, review our guide on how to flush a car cooling system before refilling it.
EPDM Versus Silicone Cummins Hoses
| Feature | MMHOSE-RAM-03DE EPDM Kit | Mishimoto Silicone Kit |
|---|---|---|
| Appearance | Factory-style black | Black, blue or red |
| Material | EPDM rubber | Reinforced silicone |
| Best use | Stock replacement and work trucks | Modified or appearance-focused builds |
| Fitment | Factory-style | Factory-style |
| Upper and lower hoses | Included | Included |
| Warranty | Mishimoto Lifetime Warranty | Mishimoto Lifetime Warranty |
EPDM is generally the practical choice for an original-style replacement. Silicone offers increased temperature and pressure tolerance but usually costs more. Neither option adds horsepower, although new hoses may prevent your horsepower from escaping in a cloud of coolant steam.
Frequently Asked Questions
What is the part number for this Mishimoto hose kit?
The OEM-style EPDM replacement kit is MMHOSE-RAM-03DE.
What trucks does MMHOSE-RAM-03DE fit?
It fits select 2003–2010 Dodge Ram 2500 and 3500 trucks with the 5.9L or 6.7L Cummins. Catalog coverage also includes applicable 2008–2010 Ram 4500 and 5500 chassis-cab models with the 6.7L Cummins.
Which years use the 5.9L Cummins?
The listed 2003 through early-2007 applications use the 5.9L Cummins. Engine availability can vary by production date, so verify the emissions label or VIN.
Which years use the 6.7L Cummins?
The 6.7L Cummins arrived during the 2007 model year, commonly identified as 2007.5, and continues through the remaining 2008–2010 applications covered by this kit.
Does it fit a Ram 1500?
No. This kit is intended for Cummins-powered heavy-duty trucks, not the gasoline-powered Ram 1500.
Are the upper and lower hoses included?
Yes. The kit includes both primary radiator hoses.
Are clamps included?
Yes. Mishimoto lists high-quality worm-gear clamps as part of the package.
Is this the silicone kit?
No. MMHOSE-RAM-03DE uses OEM-quality EPDM. Mishimoto sells a separate reinforced silicone version under the MMHOSE-RAM-03D product family.
Does this kit include the 6.7L heater hose?
No. The upper heater-hose assembly is a separate component. Mishimoto offers a dedicated heater-hose upgrade for applicable 6.7L trucks.
Will new hoses fix overheating while towing?
Only if the old hoses are leaking, restricted or collapsing. Radiator condition, fan-clutch operation, thermostat function, coolant level and water-pump performance must also be checked.
Official product details are available from the Mishimoto MMHOSE-RAM-03DE replacement hose kit page.
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