The 1991 Ford Aerostar has no open NHTSA recalls. Owners report 6 recurring issue clusters, led by “Driveshaft and transfer case failure with vibration.” Ford uses the Intelligent Oil-Life Monitor (IOLM) to determine when oil changes are due based on actual driving load — not just mileage. Ford's published cap is 10,000 miles or 1 year, whichever comes first. The schedule below reflects Ford's Normal service intervals; F-Series trucks and Super Duty have additional towing-specific items.
No open recalls on file. NHTSA lists no unrepaired safety recalls for this year, make and model. A recall can be issued at any time, and a specific car can still have one open — check yours by VIN at nhtsa.gov/recalls.
What drivers and federal regulators have officially reported about the 1991 Ford Aerostar.
POWER TRAIN
15 NHTSA complaints · 1996-06 → 2004-05
“DEFECTIVE DRIVE SHAFT/TRANSFER CASE CAUSED EXCESSIVE VIBRATION TO THE DRIVE LINE”
“CONSUMER WAS TRAVELING ABOUT 75MPH ON HIGHWAY WHEN DRIVESHAFT BENT, CAUSING THE FAILURE OF THE TRANSFER CASE AND TRANSMISSION”
“WHILE DRIVING THE TRANSFER CASE AND TRANSMISSION VIBRATE AND BECOME DETACHED AT HIGHWAY SPEEDS”
POWER TRAIN
15 NHTSA complaints · 1996-02 → 2000-03
“AUTO-TRANSMISSION; CAN SHIFT INTO ANY GEAR AND KEY CAN BE REMOVED NOT PREVENTING FROM ROLLING”
“INTERLOCK SYSTEM FAILED, CAUSING VEHICLE TO ROLL BACKWARDS INTO HOUSE”
“WHEN TRUCK WAS IN PARK POSITION WITH NO KEY, THE TRANSMISSION LEVER CAN BE TAKEN OUT OF PARK”
SERVICE BRAKES, HYDRAULIC
24 NHTSA complaints · 1996-02 → 2004-08
“THE DEFECTIVE REAR ABS BRAKING SYSTEM MALFUCTIONS, CAUSING THE REAR BRAKES TO LOCK UP AND SKID, ALMOST RESULTING IN AN ACCIDENT”
“ANTI LOCK BRAKES LOCKING UP, CAUSING VEHICLE TO VIBRATE”
“FAILURE ON THE ABS BRAKES LOSS THE OF THE BRAKING SYSTEM”
STRUCTURE
10 NHTSA complaints · 1996-02 → 2002-10
“SLIDING DOOR FAILURE, WHEN SHUTTING THE DOOR , IT COMES OFF TRACK AT THE TOP”
“SIDE DOOR WHICH SLIDES WILL RETAIN IN THE OPEN POSITION, WILL ROLL BACK VERY QUICKLY VERY GREAT FORCE”
“PASSENGER SIDE SLIDING DOOR WILL NO LONGER OPEN”
ELECTRICAL SYSTEM
54 NHTSA complaints · 1996-02 → 2005-05
“IGNITION SWITCH, ELECTRICAL SHORT, SAFETY RELATED, VEHICLE WAS PARKED, STEERING COLUMN FIRE”
“WHILE PARKED, STEERING COLUMN BEGAN SMOKING/BURNING PLASTIC WIRE IN COLUMN. OWNER DISCONNECTED BATTERY TERMINAL”
“IGNITION SWITCH SHORTED, CAUSING FIRE”
VEHICLE SPEED CONTROL
21 NHTSA complaints · 1996-01 → 2002-06
“AS CONSUMER TRIED TO PULL FORWARD, ENGINE REVVED AND VEHICLE ACCELERATED. PEDAL WAS STUCK ALL THE WAY TO FLOOR, VEHICLE WAS STOPPED BY CONCRETE WALL AFTER ABOUT 40 FT”
“WHEN HUSBAND STARTED VEHICLE IT SUDDENLY ACCELERATED WITHOUT PRIOR WARNING, COLLISION RESULTED”
“WHILE THE VEHICLE WAS IN PARK, THE VEHICLE SUDDENLY ACCELERATED”
Issues on other model years
Source: NHTSA Office of Defects Investigation (ODI). Complaint data refreshed Sep 20, 2026. Investigation data refreshed Sep 20, 2026.
We display NHTSA's record with attribution; we don't editorialize on what these complaints mean for any specific vehicle.
Critical for safety and preventing major damage
Replace synthetic-blend or full-synthetic Motorcraft oil per the IOLM, or every 7,500-10,000 miles. EcoBoost engines require full synthetic; Coyote 5.0L V8 specifies SAE 5W-30.
Estimated cost — typical U.S. ranges
Dealer
~$120–$160
Shop
~$85–$115
DIY
~$25–$55
Full synthetic costs more than conventional. 5-quart 0W-20 + filter is the typical bill.
Rotate tires every 10,000 miles, or with every other oil change. F-150 4x4 owners should rotate every 5,000-7,500 miles to even out drivetrain bias wear.
Estimated cost — typical U.S. ranges
Dealer
~$85
Shop
~$60
DIY
Free
Often free at the shop where you bought the tires — worth asking before paying.
Inspect brake pads, rotors, and brake fluid level every 10,000 miles. Front pads on F-150 and Explorer typically last 40,000-60,000 miles.
Estimated cost — typical U.S. ranges
Dealer
~$85
Shop
~$60
DIY
Free
Most shops do this free as a courtesy with any service. Don't pay separately if you can avoid it.
Ford specifies brake fluid replacement on an inspection basis, but moisture testing every 3 years is recommended. Replace if reading exceeds 3% water content.
Estimated cost — typical U.S. ranges
Dealer
~$180–$200
Shop
~$125–$140
DIY
~$10–$25
DOT 3 or 4 — match the cap. Vacuum bleeders make this a one-person DIY.
Keeps your vehicle running smoothly and efficiently
Replace the engine air filter every 30,000 miles. EcoBoost turbocharged engines are sensitive to airflow restriction — don't extend.
Estimated cost — typical U.S. ranges
Dealer
~$60–$95
Shop
~$45–$70
DIY
~$15–$40
5-minute job on most cars; the airbox lid usually has clips, no tools needed.
Ford 6R80, 10R80, and 8F transmissions use Mercon LV fluid rated 150,000 miles under normal service. Severe service (towing, plowing) drops this to 60,000 miles.
Estimated cost — typical U.S. ranges
Dealer
~$330–$500
Shop
~$235–$355
DIY
~$60–$180
Some sealed transmissions have no dipstick — fill is precise and best left to a shop. Many drivers can still DIY drain-and-fill.
On 4x4 models, replace transfer case fluid every 60,000 miles. Use Motorcraft XL-12 — do not substitute generic transfer case fluid.
Estimated cost — typical U.S. ranges
Dealer
~$105–$140
Shop
~$75–$100
DIY
~$15–$40
AWD/4WD vehicles only. Easy drain-and-fill on most platforms.
F-Series and Expedition: replace rear axle fluid every 100,000 miles, or 50,000 miles if towing. Limited-slip rear ends require friction-modifier additive.
Estimated cost — typical U.S. ranges
Dealer
~$150–$195
Shop
~$105–$135
DIY
~$20–$50
Drain plug + fill plug — straightforward DIY. AWD vehicles have two; budget for both.
Iridium spark plugs on Coyote 5.0L, EcoBoost 2.7L/3.5L, and 2.3L are rated 100,000 miles. EcoBoost engines: never exceed the interval — gap erosion causes coil failure.
Estimated cost — typical U.S. ranges
Dealer
~$285–$390
Shop
~$200–$275
DIY
~$25–$100
Iridium plugs cost more but last 100k+ miles. V6/V8 access varies wildly — some are tough.
Motorcraft Orange (Dex-Cool compatible) coolant: first change at 100,000 miles, then every 50,000. Older trucks with Yellow Motorcraft coolant: 50,000 miles throughout.
Estimated cost — typical U.S. ranges
Dealer
~$285–$330
Shop
~$200–$235
DIY
~$25–$60
Use the manufacturer-specified coolant — wrong color/chemistry can damage the cooling system.
Extends the life of your vehicle and improves comfort
Replace the cabin air filter every 20,000 miles. On F-150, located behind the glove box; on Escape and Explorer, accessed from the passenger footwell.
Estimated cost — typical U.S. ranges
Dealer
~$60–$95
Shop
~$45–$70
DIY
~$15–$40
Usually behind the glovebox. Shops charge labor for a 10-minute job — easy DIY win.
Typical U.S. ranges. Actual quotes vary by shop, parts choice, and vehicle condition.
How we estimate: Dealer = OEM parts × 1.4 + labor × $165/hr. Shop = parts + labor × $115/hr. DIY = parts only.
This maintenance schedule for the 1991 Ford Aerostar reflects Ford's published service intervals and the Intelligent Oil-Life Monitor system. Your actual service needs may vary based on driving conditions, climate, and vehicle usage. Always consult your owner's manual for model-specific recommendations.