The 1990 Ford Aerostar and the 1989 model share a similar design and platform, as they are part of the same generation of minivans. However, the 1990 model introduced some minor updates, including improvements in interior features and safety enhancements. Overall, while they maintain a similar overall appearance and functionality, the 1990 Aerostar has subtle refinements that differentiate it from the 1989 version.
The 1990 Ford Aerostar Maintenance Information manual says 21 gallons.
how do you fix a gas guage on a 1989 ford aerostar
The fuel cut off switch is bad! Replace it
It is inside the fuel tank.
In a 1990 Ford Aerostar : You either have the 3.0 liter V6 engine or the 4.0 liter V6 engine from the factory ( each size of engine has 6 engine cylinders )
On the 1989 Aerostar it is under the dash near the passenger door.
Electric or manual?
The distributor for a 3.0 liter in a 1990 Ford Aerostar rotates CLOCKWISE ( looking from the top ) The spark plug firing order is ( 1 - 4 - 2 - 5 - 3 - 6 ) The engine cylinder locations are numbered : 3 - 6 2 - 5 1 - 4 front of Ford Aerostar
At least some Aerostars (like the 1990 3 liter) do not have an EGR valve, they use a 3 way catalytic converter.
sounds like typical transmission problem
According to my book it should be 21 gallons.
On a 1989 Ford Aerostar : I believe the oil pressure sending unit for the oil pressure gauge on the 4.0 liter EFI , V6 engine is on the drivers side of the engine below the power steering pump