Description
New Ford / Mazda 4.0L OHV Cylinder Heads Pair β Ranger, Bronco, Explorer (1990β1995)
Premium Cast Iron OEM-Quality Replacement β Fully Assembled
Restore your engineβs mechanical integrity with this pair of all-new 4.0L OHV ‘Cologne’ cylinder heads, specifically engineered for 1990β1995 Ford Explorer, Ranger, and Mazda B4000 applications. These fresh, high-density cast iron units feature reinforced internal water jackets and an upgraded deck thickness to eliminate the thermal stress cracking common between the intake and exhaust seats in original thin-wall factory castings. Although the gasket surfaces are pre-milled, every unit undergoes an in-house precision verification to ensure the Surface Roughness (Ra) meets the strict requirements for modern composite head gaskets, preventing localized hot spots and chronic coolant seepage. We perform final guide sizing and multi-angle valve seat cutting on our Rottler equipment to ensure perfect valvetrain geometry and a 100% airtight seal. Pressure tested to 60 PSI and built to exceed OEM durability standards, this pair provides a permanent, professional-grade solution for the 4.0L OHV platform.
π οΈ In-House Machining Process
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Debris-Free Preparation:Β Every new casting is chemically cleaned and blown out to remove all residual machining oils, metal shavings, and manufacturing debris. This ensures your oiling system remains uncontaminated from the first start-up.
- In-House Precision Machining:Β Unlike βshelf-stockβ heads, we perform all final machine work in-house. This includesΒ final guide sizingΒ andΒ precision valve seat cuttingΒ to ensure perfect geometry and clearances before the head reaches the assembly bench.
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Pressure & Integrity Testing:Β To go beyond the factory standard, we pressure-test every head toΒ 60 PSI. This verifies that the casting is free of porosity leaks or internal defects that could compromise the cooling or oiling systems.
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Dimensional Inspection:Β Our technicians perform a multi-point inspection of the gasket-sealing surface and bore alignment. This ensures the head is perfectly flat and meets tight OEM tolerances for a flawless fit.
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Professional Assembly & Setup:Β Valvetrain components are installed and verified in a clean-room environment. We check spring heights and seal seating to ensure the assembly is balanced and ready for high-performance use.
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Vacuum-Seal Verification:Β Every intake and exhaust port isΒ Vacuum Tested. This guarantees a 100% airtight seal between the valves and seats, ensuring maximum compression and peak performance right out of the box.
π Technical Specifications
- Engine Size: 4.0L OHV
- Condition: New
- Components Included: Fully assembled with valves, springs, and seals
- Torque Spec: Rocker arm torque specification is 30 ft-lbs
- Quantity: Sold as a pair (2 cylinder heads)
- No Core Return Required
- Each Cylinder Head Includes: Valves and Springs Installed
π Fitment Data
Common Applications:
- Ford Aerostar: 1990β1994 Ford Aerostar 6-245 (4.0L)
- Ford Explorer: 1991β1994 Ford Explorer (4.0L)
- Mazda B4000: 1994 Mazda B4000 (4.0L)
- Mazda Navajo: 1991β1994 Mazda Navajo (4.0L)
- Ford Ranger: 1990β1994 Ford Ranger 6-245 (4.0L OHV)
[+] Click to View Full Detailed Fitment List
1991 Ford Aerostar 4.0L
1992 Ford Aerostar 4.0L
1993 Ford Aerostar 4.0L
1994 Ford Aerostar 4.0L
1991 Ford Explorer 4.0L
1992 Ford Explorer 4.0L
1993 Ford Explorer 4.0L
1994 Ford Explorer 4.0L
1990 Ford Ranger 4.0L
1991 Ford Ranger 4.0L
1992 Ford Ranger 4.0L
1993 Ford Ranger 4.0L
1994 Ford Ranger 4.0L
1994 Mazda B4000 4.0L
1991 Mazda Navajo 4.0L
1992 Mazda Navajo 4.0L
1993 Mazda Navajo 4.0L
1994 Mazda Navajo 4.0L
π¦ Core Return & Warranty
- β NO CORE REQUIRED β No core fee, no return needed. Your old part is yours to keep or dispose of as you see fit.
- Warranty: 2-Year Unlimited Mileage Warranty included. Click here for Warranty details.
- Please Note: Parts, marine, and performance items carry specific warranty limitations β please review our full Warranty Policy for details.





