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Call or Text (352) 722-5295Cooling parts on the 2010-2018 RAM 6.7L Cummins
The 6.7L Cummins cooling system is simple on paper: a belt-driven water pump, a thermostat, a 16 psi cap, about 29.5 quarts of coolant, and an aluminum radiator cooling a cast-iron block and head. The parts that get serviced over a truck's life are the thermostat, the cap, the hoses, and the fan clutch and shroud. Ram listed an improved cooling system among its 2013 changes, and many listings here are split at that year.
What wears out and why
- Hoses. Older hoses can collapse under a vacuum fill. Owners of 2014-2017 trucks also report overheating with a ruptured hose while towing.
- Fan clutch and shroud. Both are service items, and 2014-2017 owners report the shroud pulling into the radiator under tow.
- The cap. A cap that holds 5-6 psi instead of 16 cuts the boil-over margin.
- Drain petcocks. They have plastic threads and strip if overtightened.
- A hard upper hose is not always a hose problem. An upper hose that is stiff and pressurized on a cold engine, along with coolant pushed out of the degas bottle, is an early sign of a head gasket starting to lift. That pattern turns up at 100,000-200,000 miles on trucks that tow hard or have been tuned.
Stock replacement vs. upgrade
For a straight repair, OEM-style parts put the truck back the way it left the factory: Dayco curved radiator hoses and molded heater hoses, Dorman hose assemblies and thermostat housings, the genuine Cummins 5627589 thermostat, Mahle gaskets and seals, and XDP and Alliant Power temperature sensors. If you want to go past stock, there are Mishimoto silicone radiator hose kits, a Mishimoto top heater hose upgrade, aluminum coolant Y-pipes from Mishimoto and S&B, metal heater hose connectors from Dorman and PPE, and Fleece coolant bypass parts. Fleece's bypass kits add an auxiliary-port thermostat housing and a bypass hose to improve coolant flow to the rear cylinders, and they leave the emissions equipment alone.
What we carry
- Fleece Performance Engineering: coolant bypass parts including the FPE-CLNTBYPS-CUMMINS-SER-KIT service kit, and the FPE-CUMM-CYL-M22-PG M22 thermostat plug for cylinder heads.
- Dayco: curved upper and lower radiator hoses and molded heater inlet and outlet hoses, split by year.
- Dorman: radiator and heater hose assemblies, the 902-3044 thermostat housing, the 800-418HP metal heater hose connector, the 603-778 recovery tank and the 622-012 fan clutch.
- Mishimoto: silicone radiator hose kits, the MMHOSE-RAM-07HU top heater hose upgrade, the MMHOSE-RAM-13Y aluminum Y-pipe, and high- and low-temperature thermostats.
- Wehrli Custom Fabrication: the WCF100472 billet aluminum coolant tank cap and other cooling parts.
- XDP: the XD1007 coolant temperature sensor, XD688 thermostat housing and XD685 water pump bolt kits, and the XD681 Xtra Cool water pump for 2013-2018.
- Mahle: the C33356 water outlet and thermostat gasket and the K31420 water pump seal.
- S&B: the 83-1013 heater core supply hose and the 85-1000 aluminum dual-radiator Y-pipe.
- Also here: the genuine Cummins 5627589 thermostat, the Alliant Power AP63605 temperature sensor, the PPE 219020000 stainless heater hose connector, and cooling parts from CSF.
Fitment notes
Hoses are where fitment gets picky. Dayco lists the 72905 lower hose for 2010-2012, the 70040 lower for 2013-2018, and the 72869 and 70041 uppers for 2013-2014 only; Dorman's 626-819 lower hose is listed for 2015-2018. Mishimoto's silicone kits split the same way, MMHOSE-RAM-10D for 2010-2012 and MMHOSE-RAM-15 for 2015-2018. A few hoses listed for 2003-2010 cover only the 2010 model year in this range. The Mishimoto thermostats are listed for 1998.5-2013, the S&B dual-radiator Y-pipe is for 2013-2015 trucks that have two radiators, and the Mishimoto Y-pipe is listed for 2013-2014. Fleece's bypass kits come in separate 2010-2012 and 2013-2018 versions. Chassis cabs share the engine but not every part, so verify those separately, and confirm everything by VIN.
Frequently asked questions
Which radiator hose fits my truck?
It depends on the year, and sometimes on a narrower window than 2010-2012 versus 2013-2018. Some upper hoses are listed for 2013-2014 only, and some lower hoses for 2015-2018 only. Check the year range in the title and confirm by VIN before you order.
Which thermostat should I use?
The genuine Cummins 5627589 is the direct replacement and is listed for 2007.5-2026 6.7L engines. Mishimoto's high- and low-temperature thermostats are listed for 1998.5-2013, so they are only an option on 2010-2013 trucks. If you are unsure which way to go, call us.
What does a coolant bypass kit do?
Fleece's kits add an auxiliary-port thermostat housing and a bypass hose to improve coolant flow to the rear cylinders. It is an engine-cooling upgrade that leaves the emissions equipment alone. The kits are split 2010-2012 and 2013-2018, so order the one for your year.
Anything to watch for when I drain and refill?
Yes. The drain petcocks have plastic threads that strip if overtightened, and older hoses can collapse under a vacuum fill. If a hose is soft or swollen, replace it while the system is empty.
Not sure what fits? Call the shop at the number in the header, or use the fitment checker on any product page. We install everything we sell.