MH

Mack MH — MPG, VIN Decoder, Recalls, Reliability & Specs

Everything on the Mack MH — 49 recalls, common problems, the best & worst years, full specs, MPG and NHTSA safety, by model year.

Data · NHTSA & EPA · 1981–1994 · 14 model years · Updated Jul 17, 2026 · 4.0 ★★★★★★★★★★ ForCar Score
Quick answer

The Mack MH spans 1981–1994 with 49 recorded NHTSA recalls and a 4.0/5 ForCar reliability score. It delivers competitive fuel economy and NHTSA-rated safety.

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1981–1994
Years
49
Recalls
Top MPG
—★
NHTSA
0
Complaints
FIG.01
4.0/5
★★★★★★★★★★
ForCar Reliability Score
Our editorial rating · 14 model years
Mack MH
Safety (NHTSA)3.5
Recall record3.8
Complaint severity5.0

How we score: NHTSA crash-test safety (40%), recall frequency across all years (25%) and the share of owner complaints involving a crash, fire or injury (35%). Based on NHTSA & EPA data — not user reviews.

Overview

The Mack MH is one of the most popular vehicles in its class, produced from 1981 to 1994 across multiple generations.

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How to read a Mack MH VIN — every digit explained

Every Mack MH carries a unique 17-character VIN stamped at the factory. Each position is a code — together they spell out where, when and how your car was built. Here's exactly what every digit means.

FIG.02
1–3 · WMI1M1
4–8 · VDSCM826
9 · Check5
10 · YearR
11 · PlantA
12–17 · Serial004352
  • WMI (1–3) — country & manufacturer. Tells you it's a Mack and the country it was built in (real Mack codes below).
  • VDS (4–8) — model, body style, engine, trim & restraints. The 8th digit is the engine code.
  • Check digit (9) — a math check that proves the VIN is genuine.
  • Model year (10) — the year it was built (e.g. R = 2024, S = 2025).
  • Plant (11) — which factory assembled this MH.
  • Serial (12–17) — the unique sequential production number.
Real Mack WMIs — the first 3 VIN digits by build country
  • USA1M1
  • Canada2M1
17 CHARS·SOURCE SAE / ISO 3779 · NHTSA vPIC

Digits 4–17 — the engine code (8th), model-year letter (10th) and plant — follow the universal SAE standard, identical on every car. For the full year-code table (2001–2026), country codes and where the VIN is stamped on your MH, see the complete guide to reading a VIN.

How many recalls does the Mack MH have?

The Mack MH has 49 recorded NHTSA recalls across 1981–1994. Pick a year below to see its recalls — then verify open recalls against your specific VIN.

1993 Mack MH recalls 1

Trailer Hitches93V024000

What's wrong. The carrier yoke bolts were manufactured with worn rolling thread dies, causing stress concentrations which caused cracks during the quenching process.

Risk. This condition can cause bolt failure and allow thedriveline to separate from the carrier assembly.

Fix. Replace the carrier yoke bolts.

1992 Mack MH recalls 2

Vehicle Speed Control94V032000

What's wrong. Fuel injection system reconfiguration to comply with engine emission standards cause higher engine vibration levels which lead to early wear and complete failure of the secondary throttle return mechanism.

Risk. In the event the primary throttle return fails, failure of the secondary throttle return system would not provide protection against loss of throttle control.

Fix. A new production secondary throttle return system configuration will be installed.

Trailer Hitches93V024000

What's wrong. The carrier yoke bolts were manufactured with worn rolling thread dies, causing stress concentrations which caused cracks during the quenching process.

Risk. This condition can cause bolt failure and allow thedriveline to separate from the carrier assembly.

Fix. Replace the carrier yoke bolts.

1991 Mack MH recalls 1

Vehicle Speed Control94V032000

What's wrong. Fuel injection system reconfiguration to comply with engine emission standards cause higher engine vibration levels which lead to early wear and complete failure of the secondary throttle return mechanism.

Risk. In the event the primary throttle return fails, failure of the secondary throttle return system would not provide protection against loss of throttle control.

Fix. A new production secondary throttle return system configuration will be installed.

1990 Mack MH recalls 1

Vehicle Speed Control94V032000

What's wrong. Fuel injection system reconfiguration to comply with engine emission standards cause higher engine vibration levels which lead to early wear and complete failure of the secondary throttle return mechanism.

Risk. In the event the primary throttle return fails, failure of the secondary throttle return system would not provide protection against loss of throttle control.

Fix. A new production secondary throttle return system configuration will be installed.

1989 Mack MH recalls 2

Vehicle Speed Control94V032000

What's wrong. Fuel injection system reconfiguration to comply with engine emission standards cause higher engine vibration levels which lead to early wear and complete failure of the secondary throttle return mechanism.

Risk. In the event the primary throttle return fails, failure of the secondary throttle return system would not provide protection against loss of throttle control.

Fix. A new production secondary throttle return system configuration will be installed.

Suspension:front89V079000

What's wrong. Torque rod bolts are grade 2 instead of grade 5, which is not to specification, and could fail.

Risk. Bolt failure could allow the rear axle to shift; thiscould adversely affect truck control and could result in a crash.

Fix. Replace torque rod bolts with bolts of the proper specification.

1988 Mack MH recalls 4

Seat Belts:rear/other89V024000

What's wrong. Seat tether belt 11.0 inches long was installed instead of the 8.5 inches long belt required for this chassis.

Risk. Incorrect length belt may not properly restrain occupantand would not comply with fmvss 210.

Fix. Install correct 8.5 inch seat tether belt.

Suspension:rear:springs89V033000

What's wrong. Dowels may have been omitted during spring cap installation; this would put shear load on the four (4) spring cap bolts.

Risk. This could result in loosening and failure of the boltswith possible loss of control and accident potential.

Fix. Install the missing dowels to prevent movement between the spring cap and axle housing.

Seat Belts88V147000

What's wrong. Seat tether belts may not have been adjusted during assembly.

Risk. During an impact, driver and/or rider can move forwardand possibly strike the windshield, even when wearing a seat belt.

Fix. Adjust seat tether belt if necessary.

Vehicle Speed Control94V032000

What's wrong. Fuel injection system reconfiguration to comply with engine emission standards cause higher engine vibration levels which lead to early wear and complete failure of the secondary throttle return mechanism.

Risk. In the event the primary throttle return fails, failure of the secondary throttle return system would not provide protection against loss of throttle control.

Fix. A new production secondary throttle return system configuration will be installed.

1987 Mack MH recalls 6

Steering:linkages87V166000

What's wrong. On right hand steering arm, keyway may be in the wrong location causing a toggle condition to occur under certain conditions.

Risk. This could result in slow steering return without priorwarning which would affect steering control and create the potential for acrash.

Fix. Replace incorrect steering arm.

Steering:linkages87V179000

What's wrong. Cross steering levers may be improperly heat treated and subject to fail during normal operation.

Risk. Such failure could cause loss of truck control withoutprior warning and result in a crash.

Fix. Install new, properly heat treated steering lever.

Steering:linkages87V187000

What's wrong. The pitman arm to drag link angle is out of phase.

Risk. Under certain conditions, steering linkage could go intoa toggle condition resulting in a slow wheel return and impaired steeringcontrol, creating the potential for a vehicle crash without prior warning.

Fix. Replace mismarked pitman arm.

Seat Belts:rear/other89V024000

What's wrong. Seat tether belt 11.0 inches long was installed instead of the 8.5 inches long belt required for this chassis.

Risk. Incorrect length belt may not properly restrain occupantand would not comply with fmvss 210.

Fix. Install correct 8.5 inch seat tether belt.

Seat Belts88V147000

What's wrong. Seat tether belts may not have been adjusted during assembly.

Risk. During an impact, driver and/or rider can move forwardand possibly strike the windshield, even when wearing a seat belt.

Fix. Adjust seat tether belt if necessary.

Vehicle Speed Control94V032000

What's wrong. Fuel injection system reconfiguration to comply with engine emission standards cause higher engine vibration levels which lead to early wear and complete failure of the secondary throttle return mechanism.

Risk. In the event the primary throttle return fails, failure of the secondary throttle return system would not provide protection against loss of throttle control.

Fix. A new production secondary throttle return system configuration will be installed.

1986 Mack MH recalls 3

Structure86V008000

What's wrong. Left or right cab step may crack in its welded area due to flexing of the step during entering and exiting. Consequence of defect: as the cracks extend, the tubular step could partially collapse and break without warning to the user, and could result in personal injuries.

Fix. Install a reinforcement brace if no cracks are found. In addition, replace step if cracks are present.

Steering:linkages87V166000

What's wrong. On right hand steering arm, keyway may be in the wrong location causing a toggle condition to occur under certain conditions.

Risk. This could result in slow steering return without priorwarning which would affect steering control and create the potential for acrash.

Fix. Replace incorrect steering arm.

Seat Belts88V147000

What's wrong. Seat tether belts may not have been adjusted during assembly.

Risk. During an impact, driver and/or rider can move forwardand possibly strike the windshield, even when wearing a seat belt.

Fix. Adjust seat tether belt if necessary.

1985 Mack MH recalls 5

Structure86V008000

What's wrong. Left or right cab step may crack in its welded area due to flexing of the step during entering and exiting. Consequence of defect: as the cracks extend, the tubular step could partially collapse and break without warning to the user, and could result in personal injuries.

Fix. Install a reinforcement brace if no cracks are found. In addition, replace step if cracks are present.

Structure:body:bumpers85V051000

What's wrong. The flip out step clevis on the bumper may fail and break under the weight of the person standing on the step to service the front area of the vehicle. Consequence of defect: this sudden break will cause the person standing on the step to fall, without warning, and could result in injuries.

Fix. Remove the step clevis and replace with a new improved clevis.

Steering:linkages:drag:link:connection85V057000

What's wrong. The drag links may have been installed incorrectly allowing drag link clamp bolt to axle beam interference. Consequence of defect: during a turning maneuver, increased steering effort or complete lockup of steering could occur without warning. This could result in loss of truck control and a crash.

Fix. Assure that drag links are installed to correct interference condition.

Service Brakes, Air85V113000

What's wrong. The dual double check valve may not release the proper air volume to the brake system, causing a slight timing delay between the tractor and the trailer brake system. Consequences of defect: if the brakes are suddenly applied, the trailer could jackknife without warning to the operator, which could result in a vehicle crash.

Fix. Install two new sleeves in the dual double check valve which will increase air flow.

Seat Belts88V147000

What's wrong. Seat tether belts may not have been adjusted during assembly.

Risk. During an impact, driver and/or rider can move forwardand possibly strike the windshield, even when wearing a seat belt.

Fix. Adjust seat tether belt if necessary.

1984 Mack MH recalls 9

Structure86V008000

What's wrong. Left or right cab step may crack in its welded area due to flexing of the step during entering and exiting. Consequence of defect: as the cracks extend, the tubular step could partially collapse and break without warning to the user, and could result in personal injuries.

Fix. Install a reinforcement brace if no cracks are found. In addition, replace step if cracks are present.

Steering: Steering Wheel/handle Bar84V033000

What's wrong. Improper steering clamp bolts and torque applied during installation. The bolt could fail, allowing the steering yoke to become loose.

Fix. Inspection and, if necessary, installation of proper steering shaft clamp bolts tightened to specifications.

Trailer Hitches:fifth Wheel Assembly84V140000

What's wrong. Due to improper and inadequate welding practices, the fifth wheel on the involved vehicles is defective. Frame mounted supports may have incomplete or poor quality welds. The welds could subsequently fail allowing separation of the tractor from the trailer.

Fix. The dealer will inspect and remove the fifth wheel and reweld the mounting angles at no charge to the owner.

Latches/locks/linkages:doors:latch84V141000

What's wrong. The door latches may be defective because a pawl spring was not manufactured to specifications. The pawl spring does not create proper tension on the pawl, (a part of the door latch mechanism). This constitutes a non-compliance with the requirements of federal motor vehicle safety standard no. 206, "door latches and door retention components".

Fix. The dealer will inspect and replace door latches, if necessary.

Suspension:front:springs:leaf Spring Assembly84V142000

What's wrong. The spring center bolt is not the proper size or length. As a result, location and alignment of the spring to the front axle may not be correct. If the front spring clips loosen, the inadequate center bolt may result in spring to axle misalignment, shifting of the axle, and loss of steering control.

Fix. The defect will be corrected by the addition of a spacer between the spring and the center bolt head to increase the effective head length. A longer center bolt will also be installed for positive retention.

Structure:body:bumpers85V051000

What's wrong. The flip out step clevis on the bumper may fail and break under the weight of the person standing on the step to service the front area of the vehicle. Consequence of defect: this sudden break will cause the person standing on the step to fall, without warning, and could result in injuries.

Fix. Remove the step clevis and replace with a new improved clevis.

Steering:linkages:drag:link:connection85V057000

What's wrong. The drag links may have been installed incorrectly allowing drag link clamp bolt to axle beam interference. Consequence of defect: during a turning maneuver, increased steering effort or complete lockup of steering could occur without warning. This could result in loss of truck control and a crash.

Fix. Assure that drag links are installed to correct interference condition.

Service Brakes, Air85V113000

What's wrong. The dual double check valve may not release the proper air volume to the brake system, causing a slight timing delay between the tractor and the trailer brake system. Consequences of defect: if the brakes are suddenly applied, the trailer could jackknife without warning to the operator, which could result in a vehicle crash.

Fix. Install two new sleeves in the dual double check valve which will increase air flow.

Seat Belts88V147000

What's wrong. Seat tether belts may not have been adjusted during assembly.

Risk. During an impact, driver and/or rider can move forwardand possibly strike the windshield, even when wearing a seat belt.

Fix. Adjust seat tether belt if necessary.

1983 Mack MH recalls 8

Structure86V008000

What's wrong. Left or right cab step may crack in its welded area due to flexing of the step during entering and exiting. Consequence of defect: as the cracks extend, the tubular step could partially collapse and break without warning to the user, and could result in personal injuries.

Fix. Install a reinforcement brace if no cracks are found. In addition, replace step if cracks are present.

Steering: Steering Wheel/handle Bar84V033000

What's wrong. Improper steering clamp bolts and torque applied during installation. The bolt could fail, allowing the steering yoke to become loose.

Fix. Inspection and, if necessary, installation of proper steering shaft clamp bolts tightened to specifications.

Service Brakes, Air:supply:check Valve84V035000

What's wrong. A manufacturing error resulted in the installation of carbon steel springs in some dual-compartment air reservoir check valves. Carbon steel springs are inadequate for this application because they are subject to severe corrosion and subsequent failure of the check valve.

Fix. The carbon steel spring will be replaced with a stainless steel one.

Trailer Hitches:fifth Wheel Assembly84V140000

What's wrong. Due to improper and inadequate welding practices, the fifth wheel on the involved vehicles is defective. Frame mounted supports may have incomplete or poor quality welds. The welds could subsequently fail allowing separation of the tractor from the trailer.

Fix. The dealer will inspect and remove the fifth wheel and reweld the mounting angles at no charge to the owner.

Structure:body:bumpers85V051000

What's wrong. The flip out step clevis on the bumper may fail and break under the weight of the person standing on the step to service the front area of the vehicle. Consequence of defect: this sudden break will cause the person standing on the step to fall, without warning, and could result in injuries.

Fix. Remove the step clevis and replace with a new improved clevis.

Steering: Steering Wheel/handle Bar83V100000

What's wrong. Under severe strain, a defective weld joining the steering wheel hub to the hub perimeter could fail, causing the steering wheel to separate from the vehicle.

Fix. Defective steering wheels will be replaced at no charge to owner.

Service Brakes, Air85V113000

What's wrong. The dual double check valve may not release the proper air volume to the brake system, causing a slight timing delay between the tractor and the trailer brake system. Consequences of defect: if the brakes are suddenly applied, the trailer could jackknife without warning to the operator, which could result in a vehicle crash.

Fix. Install two new sleeves in the dual double check valve which will increase air flow.

Seat Belts88V147000

What's wrong. Seat tether belts may not have been adjusted during assembly.

Risk. During an impact, driver and/or rider can move forwardand possibly strike the windshield, even when wearing a seat belt.

Fix. Adjust seat tether belt if necessary.

1982 Mack MH recalls 7

Structure86V008000

What's wrong. Left or right cab step may crack in its welded area due to flexing of the step during entering and exiting. Consequence of defect: as the cracks extend, the tubular step could partially collapse and break without warning to the user, and could result in personal injuries.

Fix. Install a reinforcement brace if no cracks are found. In addition, replace step if cracks are present.

Service Brakes, Air:supply:check Valve84V035000

What's wrong. A manufacturing error resulted in the installation of carbon steel springs in some dual-compartment air reservoir check valves. Carbon steel springs are inadequate for this application because they are subject to severe corrosion and subsequent failure of the check valve.

Fix. The carbon steel spring will be replaced with a stainless steel one.

Trailer Hitches:fifth Wheel Assembly84V140000

What's wrong. Due to improper and inadequate welding practices, the fifth wheel on the involved vehicles is defective. Frame mounted supports may have incomplete or poor quality welds. The welds could subsequently fail allowing separation of the tractor from the trailer.

Fix. The dealer will inspect and remove the fifth wheel and reweld the mounting angles at no charge to the owner.

Structure:body:bumpers85V051000

What's wrong. The flip out step clevis on the bumper may fail and break under the weight of the person standing on the step to service the front area of the vehicle. Consequence of defect: this sudden break will cause the person standing on the step to fall, without warning, and could result in injuries.

Fix. Remove the step clevis and replace with a new improved clevis.

Steering: Steering Wheel/handle Bar83V100000

What's wrong. Under severe strain, a defective weld joining the steering wheel hub to the hub perimeter could fail, causing the steering wheel to separate from the vehicle.

Fix. Defective steering wheels will be replaced at no charge to owner.

Service Brakes, Air85V113000

What's wrong. The dual double check valve may not release the proper air volume to the brake system, causing a slight timing delay between the tractor and the trailer brake system. Consequences of defect: if the brakes are suddenly applied, the trailer could jackknife without warning to the operator, which could result in a vehicle crash.

Fix. Install two new sleeves in the dual double check valve which will increase air flow.

Seat Belts88V147000

What's wrong. Seat tether belts may not have been adjusted during assembly.

Risk. During an impact, driver and/or rider can move forwardand possibly strike the windshield, even when wearing a seat belt.

Fix. Adjust seat tether belt if necessary.

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Best and worst years for the Mack MH

We're still compiling NHTSA owner-complaint history for the Mack MH — best- and worst-year trends will appear here once that data is in.

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What are the most common Mack MH problems?

We're still compiling NHTSA owner-complaint data for the Mack MH — the most-reported problems will appear here once that data is in.

Source: NHTSA owner complaints, all model years. Bar = share of total complaints. Full reports searchable on NHTSA.gov.

Mack MH specifications & dimensions

The 1994 Mack MH. Full dimensions below — engine, horsepower and trim decode from your VIN. For the original factory build — MSRP, trim and standard equipment — rebuild the Mack MH window sticker.

Specs cache warming…

Source: NHTSA vPIC / Transport Canada vehicle specifications. Metric values converted to imperial; generation ranges approximate.

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Mack MH cargo space, seating & interior room

How much the MH holds — passengers and cargo. Seating, cargo and interior dimensions vary by trim and seat configuration — decode your VIN for the exact build.

Exact seating capacity, third-row availability, legroom and headroom decode from your VIN or vary by trim — the original factory equipment & options list shows what each trim included.

Passenger & cargo volume from EPA fueleconomy.gov (largest configuration). Seats, legroom and headroom from NHTSA vPIC on VIN decode.

Mack MH tire size, oil type & owner specs

The fitment owners look up most — tires, wheels, oil and batteries. Exact wheel and tire sizes decode from your VIN or the driver's door-jamb placard; the universal items are listed below.

Wheels & tires
Wheel sizeby VIN
Tire sizeby VIN
Bolt patternby trim
Tire pressure32–36 PSI
Engine oil
Oil typeFull synthetic
Gradeon oil cap
Capacityby engine
Battery
Main battery12V · group by trim
Key-fob cellCR2032
Wiper blades
Front bladesby generation
Rear bladeif equipped
Fuses
Fuse boxeshood + dash
Diagramon box lid
Light bulbs
Headlightby trim
Tail / brakeby trim
Fogif equipped

Exact tire, wheel, oil grade, capacity and battery group are added per trim and model year — decode your VIN above for the factory fitment. Universal items shown as-is.

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What MPG does the Mack MH get?

MPG cache warming… reload in a moment.

What engines does the Mack MH have? Power & range

Powertrain data warming… reload in a moment.

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How much does a Mack MH cost to own?

A Mack MH holds its value well. A typical example keeps roughly 56% of its value after five years — losing about 44% to depreciation. Check what a used MH is worth today or browse current used-market prices before you buy or sell. Fuel, maintenance and insurance add to the total cost to own.

84%
Value @ 1 yr
68%
Value @ 3 yrs
56%
Value @ 5 yrs
Est. 5-yr fuel
FIG.06
$
AgeValue retainedEst. resale valueLost to depreciation
Year 184%$25,200−$4,800
Year 276%$22,800−$7,200
Year 368%$20,400−$9,600
Year 461%$18,300−$11,700
Year 556%$16,800−$13,200
ROWS 5·SOURCE ForCar estimate

What goes into the five-year cost to own:

  • Depreciation — the biggest cost: this MH loses about 44% of its value over five years. See the full depreciation curve by age.
  • Fuel — based on EPA economy at roughly 15,000 miles a year.
  • Maintenance & repairs — routine service, tires and wear items as the MH ages.
  • Insurance — varies by driver, state and trim; get a quote for your exact figure.

Resale & depreciation are ForCar estimates from typical segment value-retention curves — not a live market quote. Fuel from EPA fueleconomy.gov at ~15k mi/yr.

Is the Mack MH safe?

NHTSA crash-test ratings aren't published for the MH yet — see the top-rated safest cars instead.

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How many miles does a Mack MH last?

A well-maintained Mack MH typically lasts 250,000–300,000+ miles. It's exceptionally durable — with routine maintenance many owners report 250k+ on the original powertrain. Its ForCar Reliability Score is 4.0/5.

MH

Check your Mack MH’s VIN — history, recalls & specs

Title records, open recalls, build details and paint code — straight from the VIN. Free.

Check this MH’s VIN free →

All Mack MH model years

A year-by-year snapshot of the Mack MH — recalls, best EPA fuel economy and NHTSA safety. Tap a year for full details.

FIG.09
YearRecallsBest MPGSafety
1994 MH0
1993 MH1 recall
1992 MH2 recalls
1991 MH1 recall
1990 MH1 recall
1989 MH2 recalls
1988 MH4 recalls
1987 MH6 recalls
1986 MH3 recalls
1985 MH5 recalls
1984 MH9 recalls
1983 MH8 recalls
1982 MH7 recalls
1981 MH0
ROWS 14·SOURCE NHTSA + EPA

Recalls = NHTSA campaigns that year · MPG = best EPA combined · Safety = NHTSA overall stars (tested years).

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Frequently asked questions

What are the worst years for the MH?

We're still compiling NHTSA owner-complaint history for the Mack MH.

How many recalls does the MH have?

49 recorded NHTSA recalls across 1981–1994. Always check open recalls by your VIN.

How many miles does a MH last?

A well-maintained MH typically reaches 200,000–300,000 miles with regular maintenance.

Is the MH reliable?

Our ForCar Reliability Score for the MH is 4.0/5, based on NHTSA safety, recall history and complaint severity.

What's the Mack MH warranty?

New Mack models carry a 3 years / 36,000 miles basic (bumper-to-bumper) warranty and a 5 years / 60,000 miles powertrain warranty. Coverage can vary by model year and market — confirm with a Mack dealer.

Where is the Mack MH made?

The assembly plant is encoded in the VIN — the 11th character. Decode your MH's VIN above to see exactly where it was built; Mack may build it at more than one plant depending on the year.

How much ground clearance does the MH have?

Ground clearance varies by trim and drivetrain — AWD/4WD versions often sit higher. Decode your VIN or check the specific trim for the exact figure.

Data sourced from NHTSA (recalls, complaints, safety ratings) and EPA fueleconomy.gov (MPG). Best/worst-year analysis is ForCar's own aggregation of complaint volume. Last updated Jul 2026. — ForCar Editorial Reviewed by Denis Kataev, founder of ForCar.
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