Recipe - Ford 3.5L EcoBoost Gasoline (F-150, Expedition, Transit, Raptor - 2011-present)
Specific Fix build
Reliability tier: aggregated - verify before ordering, see /disclosure/
Internal water-pump service: the 3.5L EcoBoost carries the pump inside the front cover - a failed seal can send coolant into the oil pan (bearing damage) or leak externally. Unexplained coolant loss with no external trace is the trigger: pressure-test, inspect the oil for contamination, and treat a preventive pump+thermostat service as a known-cost decision on high-mileage tow vehicles.
Parts
- 3.5L EcoBoost Water Pump, Gen1 (current number ER3Z-8501-C) - Gen1 pump (ER3Z-8501-C), F-150 2011-2015 / Expedition-Navigator 2015-2016 / Transit 2015-2019 (qty 1)
- 3.5L EcoBoost Water Pump, Gen2 (JL3Z-8501-B) - Gen2 pump (JL3Z-8501-B), F-150 2018-2020 (qty 1)
- 3.5L EcoBoost Water Pump, Gen3 (ML3Z-8501-C) - Gen3 pump (ML3Z-8501-C), F-150 2021-2025 (qty 1)
- 3.5L EcoBoost Thermostat, Gen1-Gen2 (BL3Z-8575-B) - thermostat while the system is open (BL3Z-8575-B) (qty 1)
- 3.5L EcoBoost Thermostat Housing / Water Outlet, Gen1-Gen2 (BL3Z-8A586-G) - housing if the leak trace is at the housing (BL3Z-8A586-G) (qty 1)
Install order
- pressure-test cold and hot; trace external leaks first (hoses, degas, thermostat housing)
- inspect the oil for coolant contamination before ordering - if contaminated, the job escalates to bearings/flush
- front-cover water-pump replacement with fresh coolant and thermostat
- if the trace points at the housing: replace housing and seals
- oil + filter change immediately on any confirmed intrusion; re-check level after 500 miles
Expected outcome
Coolant loss stopped before it reaches the oil; cooling system baselined for the tow season.
Parts budget
About $30-$260 in parts. It depends on what the diagnosis finds; each option below is what you buy together. Prices marked "at Dave's" are Dave's Auto Center's, the same as in his store; the others are approximate prices from OEM and maker catalogs, rounded (a manufacturer's list price can run higher). Parts only, no labor.