Engine Ford 99X

The 4.0-liter V6 Ford 99X or 4.0 OHV engine was produced in Germany from 1990 to 2000 and was installed in the first two generations of the Explorer SUV, popular in a number of markets. A similar engine, but under a different designation, was installed on the Aerostar minibus and Ranger pickup truck.

Cologne V6 family: BRF, 99E, 99X.


Production years 1990 – 2000
Displacement, cc 3958
Fuel system distributed injection
Power output, hp 155 – 165
Torque output, Nm 298 – 314
Cylinder block cast iron V6
Block head aluminum 12v
Cylinder bore, mm 100
Piston stroke, mm 84
Compression ratio 9.0
Features OHV
Hydraulic lifters yes
Timing drive chain
Phase regulator no
Turbocharging no
Recommended engine oil 5W-30
Engine oil capacity, liter 4.7
Fuel type petrol
Euro standards EURO 1/2
Fuel consumption, L/100 km (for Ford Explorer 1993)
— city
— highway
— combined
Engine lifespan, km ~400 000
Weight, kg 203

The engine was installed on:

  • Ford Explorer 1 (UN46) in 1990 – 1994; Explorer 2 (U105) in 1994 – 2000.

Disadvantages of the Ford 99X engine

  • This is a fairly reliable and resourceful power unit and all its problems are due to old age.
  • Most complaints are related to lubricant leaks on gaskets and seals.
  • At high mileage, severe wear of the valve guides is often encountered.
  • Hydraulic compensators do not tolerate cheap oil and can begin to knock after 200 thousand km.
  • The short timing chain between the crankshaft and camshaft is stretched after 300,000 km.

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