Failure mode - 6.6L V8 Gasoline (GM HD, L8T 2020+)

Cooling system wear: water pump, hoses, thermostat (towing duty)

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

Symptoms

coolant seep from the water pump weep hole; soft hoses; temperature creep under sustained tow
the risk is being stranded on a loaded HD truck - routine inspection is the defense

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

Root cause

Normal wear of water pumps, hoses and thermostats at higher mileage, accelerated by towing duty - the same wear-item framing the vendor guide applies to the diesel sibling. No L8T cooling defect cluster is documented in the open record.

Diagnosis

pressure-test the cooling system; inspect the water pump weep hole, hoses and thermostat at service intervals

Fixes

replace the water pump / thermostat / worn hoses; refill with the specified coolant ()

Prevalence

occasional

Parts for this repair run about $40-$300: see them next to the other repairs on this engine in repair costs.