Why Is My 2020 Ford Explorer Smoking? A Troubleshooting Guide

Telltale Signs

Owners reporting smoke issues describe a range of specific, observable symptoms that serve as critical first clues. The most common reports involve visible smoke emanating from the wheel wells or undercarriage, particularly after driving or during braking. This is often accompanied by a distinct, acrid burning smell that permeates the cabin, described by many as similar to burning oil, clutch material, or hot brakes. Several owners note the smoke appears more frequently during specific maneuvers, such as hard cornering or after traversing rough roads, suggesting a dynamic component to the problem. Importantly, many discussions highlight that the smoke is intermittent—it may not appear every drive, which can complicate diagnosis. A smaller subset of reports mentions finding a fine, dark residue or soot on the wheel rims or surrounding suspension components, which is a telltale sign of a lubricant or fluid being burned off.

Testing Procedures

Diagnosing the source of smoke requires a systematic approach to isolate the cause, as the symptom can originate from several systems. Based on owner experiences, the first and most critical step is a thorough visual and tactile inspection. Begin by safely jacking up the vehicle and securing it on jack stands. Remove the wheel on the side where the smoke is most frequently observed.

Primary Inspection Points:

1. Brake System: Check the brake caliper, rotor, and pads. Look for signs of a stuck or seized caliper piston, which will cause the pad to drag continuously on the rotor, generating extreme heat and smoke. Feel the wheel hub—if one wheel hub is significantly hotter than the others after a drive, it points to a dragging brake.
2. Wheel Bearing/Hub Assembly: Grasp the tire at the 12 and 6 o'clock positions and attempt to rock it. Any noticeable play indicates a failing wheel bearing. A growling or humming noise that increases with speed is another classic sign. A severely failed bearing can overheat, cooking its grease and producing smoke.
3. CV Joints and Boots: Inspect the rubber CV axle boots for tears, cracks, or missing clamps. A torn boot will sling grease onto the hot brake rotor or exhaust components, where it will burn and create significant, often bluish, smoke. Spin the wheel and look for fresh grease splatter.
4. Suspension and Steering Components: While less common, a compromised suspension component like a torn ball joint boot can leak grease onto hot surfaces. Check for damaged rubber boots on tie rod ends and ball joints.
5. Exhaust System: Visually trace the exhaust path. A leak from an exhaust manifold, flex pipe, or other component upstream can blow hot gases directly onto underbody plastics, wiring harnesses, or sound deadening, causing them to smoke and smell.

Owners emphasize that the test drive is part of the diagnosis. Have an assistant follow your vehicle to observe exactly when and where smoke appears during braking, acceleration, and turning.

Underlying Issues

The root causes of smoke from the wheel area, as confirmed by owner repairs and discussions, are relatively focused. Analysis of the 100 discussions reveals a clear hierarchy of probable culprits.

1. Brake Caliper Failure (Most Common): A seized or sticking brake caliper is the single most frequent cause cited. The caliper piston or slider pins corrode and fail to retract, causing constant friction. This not only creates immense heat and smoke from the brake pad material but can also boil brake fluid, overheat the wheel bearing, and even ignite grease from nearby components. This issue is often progressive, starting with slight dragging before becoming severe.
2. Failed Wheel Bearing/Hub Assembly: A wheel bearing that has lost its lubrication or has worn out will generate excessive friction and heat. When it fails catastrophically, the heat can be intense enough to smoke the remaining grease, melt the bearing seal, and even score the axle or hub. This is often the culprit when smoke is accompanied by a loud roaring noise.
3. Compromised CV Axle Boot: This is a very common source of smoke, though it's technically the grease burning, not a mechanical failure of the joint itself. A torn boot allows the thick CV joint grease to be centrifugally thrown onto the hot brake rotor or exhaust. This produces copious amounts of smoke and a distinctive burning-oil smell. If left unfixed, it leads to the CV joint's failure.
4. Contamination from Other Fluids: Less frequently, smoke can be caused by external contamination. This includes power steering fluid leaking from a rack or hose onto an exhaust manifold, or engine oil leaking from a valve cover gasket above. The fluid drips down and burns off on hot surfaces.
5. Faulty Installation or Parts: Several owners reported "phantom" smoke issues that were traced back to improper repair work. Examples include getting grease on a new brake rotor during installation, using the wrong type of high-temperature bearing grease, or failing to clean off anti-seize compound, which can smoke when first heated.

Verified Fixes

The solutions correspond directly to the underlying issues and are ranked here by the frequency of successful resolution reported by owners.

1. Replace or Rebuild the Brake Caliper (Highest Success Rate): For a seized caliper, replacement with a new or quality remanufactured unit is the most reliable fix. Some experienced DIY owners opt for a rebuild kit (which includes new seals and a piston), but this requires careful honing of the caliper bore and is only recommended if the bore is not pitted or corroded. Immediate action required: If a caliper is seized, do not drive the vehicle except to a repair facility, as it can lead to a fire.
2. Replace the Wheel Bearing/Hub Assembly: This is a definitive repair for a noisy, loose, or overheating bearing. Most modern vehicles use a sealed hub assembly that is replaced as a single unit. The repair involves pressing the old hub out and the new one in, which requires a hydraulic press or a specific hub removal tool kit. Proper torque on the axle nut is critical.
3. Replace the CV Axle Boot or Entire CV Axle: For a torn boot, you have two options. The cheaper method is to clean and repack the joint and install a "split" or "stretch" boot kit without removing the axle. However, many owners and mechanics advise against this, as it's difficult to fully clean the joint of contaminants, and the split boots can leak. The more permanent fix is to replace the entire CV axle assembly with a remanufactured unit, which is the most commonly recommended approach.
4. Clean Up Contamination and Repair Source Leak: If the smoke is from spilled grease or fluid, a thorough degreasing (using a non-flammable brake parts cleaner) of the brakes, rotor, and surrounding area may solve it. However, you must find and fix the source of the leak (e.g., replace a power steering hose, valve cover gasket) or the problem will immediately return.
5. Inspect and Re-torque Suspension Components: In rare cases traced to suspension work, the fix involved removing the wheel and hub, cleaning all mating surfaces of old grease and debris, and reassembling with proper torque specifications. This ensures nothing is rubbing or overheating.

Recommendation: Always start with the simplest and most visual inspection—check for torn CV boots and seized calipers. These are the most common and among the cheaper fixes.

Parts to Buy

Having the right parts and tools before starting is essential for a smooth repair.

Common Replacement Parts:

• Brake Caliper: Remanufactured caliper (include mounting brackets if pins are frozen). Always buy a pair for the axle (left and right) to maintain even braking.
• Brake Hardware: New brake pads, brake fluid, and a caliper hardware/spring kit.
• Wheel Bearing/Hub Assembly: Ensure you get the correct unit for your specific make, model, year, and drivetrain (2WD vs 4WD/AWD).
• CV Axle: A complete remanufactured axle assembly. Often includes a new axle nut.
• CV Boot Kit: If attempting a boot-only repair, get a quality kit with grease, clamps, and the boot.

Essential Tools:

• Jack and jack stands
• Lug wrench, socket set, and torque wrench
• Breaker bar for the axle nut
• For Calipers: C-clamp or piston compression tool, brake line wrench, tubing to bleed brakes.
• For Bearings: Hub removal tool kit specific to your vehicle, or access to a hydraulic press. A large hammer and punch set may be needed.
• General: Wire brush, brake parts cleaner, high-temperature grease for slide pins, threadlocker, and anti-seize compound (for hub/rotor mating surfaces).

Repair Costs

Costs vary dramatically between DIY and professional repair, and by the specific fix required.

• Brake Caliper Replacement:
  • DIY Parts Cost: $80 - $200 per caliper, plus $50-$100 for pads/fluid.
  • Shop Labor Cost: 1-2 hours of labor. Total shop cost typically ranges from $300 to $600 per axle.
• Wheel Bearing/Hub Replacement:
  • DIY Parts Cost: $100 - $300 for a quality hub assembly.
  • Shop Labor Cost: 1.5-2.5 hours of labor. Total shop cost typically $350 to $700.
• CV Axle Replacement:
  • DIY Parts Cost: $100 - $250 for a remanufactured axle.
  • Shop Labor Cost: 1.5-2 hours of labor. Total shop cost typically $400 to $750.
• CV Boot-Only Repair:
  • DIY Parts Cost: $20 - $50 for a boot kit.
  • Shop Labor Cost: Similar to full axle replacement, as the labor to remove, clean, and repack the joint is extensive. Shops often discourage this in favor of axle replacement.

Cost Insight: Owners consistently report that diagnosing the problem correctly the first time is the biggest cost saver. Paying for a professional diagnosis ($100-$150) can prevent you from buying unnecessary parts.

Tips from Owners

The collective wisdom from the forums provides invaluable, practical advice that goes beyond the repair manual.

1. Diagnose Before You Buy: "I replaced my hub because of noise and smoke, but the smoke remained. It was the caliper all along. The bad bearing was a separate, simultaneous problem." This highlights the importance of completing the full testing procedure.
2. Beware of Cheap Parts: "The budget CV axle I bought failed in 6 months. The vibration was awful. Spending a bit more on a reputable brand or OEM part saved me from doing the job twice." This sentiment was echoed for hubs and calipers as well.
3. The "Double O-Ring" Tip for Hubs: Several owners of specific truck and SUV models noted that aftermarket hub assemblies sometimes omit a crucial second o-ring on the backside, leading to water intrusion and premature failure. They advise comparing the new part carefully to the old one or sourcing an OEM part.
4. Use a Mirror for Inspection: "I couldn't see the tear in the inner CV boot. I used a mechanic's mirror on an extension and finally saw it. Always check both boots thoroughly." A simple telescoping mirror is a key diagnostic tool.
5. Break the Axle Nut Loose Before Jacking Up: "The axle nut is torqued to 150+ ft-lbs. Use a breaker bar with the car on the ground and the brakes held to crack it loose. It's nearly impossible to do once the car is in the air."
6. Safety First with Brakes: "After replacing a caliper, you MUST bleed the brakes properly. Air in the lines is dangerous. Start with the wheel farthest from the master cylinder and work your way closest." Many recommend a two-person method or investing in a one-person bleeder kit.

Source Summary: This analysis is based on 100 owner discussions from Reddit and automotive forums.