Failure mode - Ram ProMaster 3.6L Pentastar V6 (2014-2025)

Cooling: water pump, thermostat housing and coolant bottle leaks

Reliability tier: aggregated - verify before ordering, see /disclosure/

Symptoms

coolant smell/weep at the water pump weep hole
coolant loss with visible crust at the thermostat housing
overheat episodes after level loss

Compare with the other causes of the same sign on this engine: losing coolant (2 causes) · overheating or temperature creeping up

Root cause

The strongest NHTSA cluster on the gas ProMaster (38 complaints, 2018-2023-heavy): water pump weep, thermostat housing leaks and coolant bottle cracks. All are service-routine items once located; the housing and bottle are plastic parts.

Diagnosis

pressure-test the system; inspect weep hole, housing, bottle and hoses in order
check the coolant bottle for hairline cracks at the seams
replace the failed item; refill and bleed per procedure

Fixes

water pump / thermostat housing / coolant bottle replacement per findings ()

cooling - more than one option: 3.6 Pentastar Thermostat Housing (68136754AA, includes thermostat), 3.6 Pentastar Water Pump (68667064AA, current)

Prevalence

common

Parts for this repair run about $75-$220: see them next to the other repairs on this engine in repair costs.