Buy Dodge Ram 3500 Radiators

Quick Take

The Dodge Ram 3500 radiator is a metal "heat-exchanger" that keeps the big Cummins or HEMI engine from overheating. It holds roughly 5-6 gallons of coolant, uses long-life OAT antifreeze, and on some 2013-2014 models it even works in tandem with a second "auxiliary" radiator for heavy towing. Dimensions vary by model year, but a common heavy-duty aluminum core measures about 22 inches tall, 42 inches wide, and 2.5 inches thick. Knowing how it works, the signs of trouble, and the right service steps will help you avoid warped heads or surprise breakdowns.

Part Basics

A radiator (also called a cooling core or radiator assembly) is a series of narrow tubes with thin fins that shed engine heat into the passing air. Coolant absorbs heat inside the block, flows through the tubes, and gives up that heat as air rushes through the fins (Circle M Tire & Automotive). Without this process, metal parts would melt or seize.

Fit & Specs

• Typical heavy-duty aftermarket core: 22.13 in H × 41.88 in W × 2.5 in D with 1.5-inch inlet and 1.75-inch outlet (Champion Radiators)
• Complete cooling-system capacity (single-radiator trucks, 5.9 L diesel): ≈ 22 qt / 5 gal (cumminsforum.com)
• Dual-radiator trucks (2013-2015 6.7 L diesel) hold ≈ 5.7 gal (Diesel Truck Resource)

Always match the core size, hose positions, and transmission-cooler ports to your exact year, engine, and gearbox.

How It Works

1. Coolant pickup - pump pushes 50/50 water-antifreeze mix through the block.
2. Heat transfer - coolant enters the radiator tubes; fins add surface area so heat moves to air fast (Circle M Tire & Automotive).
3. Thermostat control - opens near 200 °F so flow starts; too cold and it stays closed for faster warm-up.
4. Fan assist - mechanical or electric fans pull air at low road speed.
5. Return flow - cooled liquid heads back to the water pump.

Signs of Trouble

• Temperature gauge climbing or in the red (Grayson Tire and Auto)
• Steam or sweet coolant smell under the hood (South Denver Automotive)
• Puddles of green, orange, or pink fluid on the ground (Firestone Complete Auto Care)
• Rust-colored coolant or "sludge" inside the cap (Motorist Assurance Program)
• Cracked plastic side tanks (common on OEM units from 2013-2014) (Mishimoto)

Act fast-running hot can warp cylinder heads.

Coolant & Fluids

Ram specifies Mopar 10-year / 150 000-mile OAT antifreeze meeting MS-12106 or MS-90032 (Blauparts). Stick with one chemistry; mixing old HOAT or silicate coolant with OAT can gel.

• Factory change interval: 150 000 mi or 10 years (lhmdodgeboise.com)
• Many fleet shops prefer a shorter 30 000-mile flush for severe towing (lhmchryslerjeep.com).

For quick reference, you can read Chrysler's official coolant standard here.

Maintenance Steps

1. Let engine cool; open cap slowly.
2. Drain through radiator petcock into a catch pan.
3. Remove lower and upper hoses plus fan-shroud bolts (only two on most models) (cumminsforum.com).
4. Flush with distilled water until clear.
5. Refill 50/50 OAT mix; bleed air with heater on high.
6. Verify no leaks or pressure-drop on cap tester.

Full video walk-throughs show the process on 2003-2009 and 1994-2002 trucks (Mishimoto, 1A Auto).

Upgrades & Heavy Duty

• Dual-radiator system (2013-2014 HD models) adds a front auxiliary core for extra towing capacity but has a plastic "Y" hose that often cracks (cumminsforum.com); aftermarket aluminum pipes cure the leak (Wehrli Custom Fabrication).
• All-aluminum replacements ditch plastic tanks for TIG-welded ends, boosting strength and cooling margin (Mishimoto).
• High-flow thermostats and electric fan kits reduce temps on chipped or high-altitude work trucks.

Environmental Tips

Used coolant contains ethylene glycol and metals. The U.S. EPA says it should be recycled on-site, by mobile service, or off-site-never dumped down a drain (US EPA). Learn more about safe household hazardous-waste handling here.

Frequently Asked Questions

Q: How often should I change my Ram 3500 coolant?
A: Chrysler recommends every 150 000 miles or 10 years, whichever comes first (lhmdodgeboise.com). Severe-duty trucks may benefit from 30 000-mile intervals (lhmchryslerjeep.com).

Q: What type of antifreeze does my 6.7 L Cummins require?
A: Use purple or pink Mopar OAT coolant that meets MS-12106 (premixed or concentrate) (Blauparts).

Q: How much coolant will drain out if I only open the radiator petcock?
A: About 3 gallons-roughly half the system-because the block still holds fluid (cumminsforum.com).

Q: My 2014 has two radiators. Can I bypass the front (secondary) one?
A: Technically yes, but you'll lose cooling capacity and may overheat under heavy load. Many owners replace the leaky hose or upgrade to an aluminum Y-pipe instead (cumminsforum.com, Wehrli Custom Fabrication).

Q: Why does the temp gauge spike only when towing uphill?
A: The engine makes more heat; airflow drops at low speed; and the radiator can't shed heat fast enough if fins are dirty or coolant is old (Motorist Assurance Program).

Q: What are the first signs my radiator is failing?
A: Hot gauge, steam, puddles, or brown coolant sludge. A cracked plastic tank is common on stock units (Grayson Tire and Auto, Mishimoto).

Q: Can I mix green "universal" coolant with the factory pink?
A: No. Mixing chemistries can form gel and block passages, risking an overheat (Blauparts).

Q: Is it safe to drive if I see steam?
A: No-pull over, shut off, and let it cool. Continuing can warp heads (South Denver Automotive).

Q: Do aluminum radiators corrode?
A: Far less than plastic-tank units, but they still need clean OAT coolant to prevent electrolysis (Mishimoto).

Q: How do I dispose of old coolant?
A: Take it to a recycling center; EPA guidance forbids pouring antifreeze down storm drains (US EPA).

Q: What tools do I need to swap the radiator?
A: Basic sockets, hose-clamp pliers, a catch pan, and a flat screwdriver cover most jobs (1A Auto).

Q: Can a bad cap cause overheating?
A: Yes-a weak cap lowers system pressure, coolant boils sooner, and heat transfer drops (Firestone Complete Auto Care).

Q: Why does my gauge fluctuate at idle?
A: The fan spins slower, so airflow falls. Check fan clutch and ensure fins are not blocked (Motorist Assurance Program).

Q: Does a larger radiator hurt warm-up in winter?
A: No-the thermostat stays closed until the engine reaches set temp, so warm-up time is similar.

Q: Should I change hoses when I replace the radiator?
A: Yes-old hoses can split under new pressure. Replace clamps, too (cumminsforum.com).

Q: Is distilled water required for mixing?
A: Always use distilled or de-ionized water to avoid mineral deposits inside the core (Motorist Assurance Program).

For deeper technical reading, the EPA's antifreeze recycling fact sheet and Chrysler's coolant standards provide authoritative guidance.