A Detailed Look at 2018 Jeep Engine Issues

The 2018 model year was a bold one for Jeep. It saw the launch of the totally redesigned JL Wrangler, a heavy refresh for the Grand Cherokee, and the continuation of the popular Cherokee KL platform. These vehicles arrived with a choice of engines that promised better fuel economy and more power, including the all-new 2.0L turbocharged four-cylinder and the carryover 3.6L Pentastar V6 and 5.7L/6.4L HEMI V8s.

While these powertrains have proven capable off-road, the 2018 model year is also known for a specific set of engine-related problems that have led to significant recalls, technical service bulletins (TSBs), and common owner complaints. This guide provides a comprehensive breakdown of what went wrong, what the manufacturer did to fix it, and what owners can do to keep their 2018 Jeep running reliably.

Breaking Down the Common Engine Problems

Engine issues in the 2018 Jeep lineup often stem from a handful of known weak points. We will outline the most prevalent problems by engine platform so you can quickly identify what applies to your specific vehicle.

3.6L Pentastar V6: The Workhorse Issues

The 3.6L Pentastar V6 is Jeep's most popular engine, found in nearly every model from the Wrangler to the Grand Cherokee. It is generally reliable, but the 2018 generation suffers from several chronic problems.

  • Cylinder Head Failure (Left Bank): The most serious issue involves the left (driver's side) cylinder head. A manufacturing defect in the valve guide and spring retention can cause the valve train to collapse at higher mileage. This results in a loud ticking noise, a check engine light (usually a misfire code for cylinder 1 or 2), and significant power loss. This often requires a complete cylinder head replacement.
  • Oil Cooler Housing Leaks: The OEM oil cooler and filter housing is made of plastic. The part sits on top of the engine and is exposed to extreme heat cycles. Over time, the plastic housing warps and cracks, causing external oil leaks and sometimes internal coolant contamination (the oil cooler uses engine coolant). If the housing fails, the oil pressure drops rapidly, which can damage the engine bearings.
  • Excessive Oil Consumption: A major complaint for the 2018 Pentastar is burning oil at a high rate, sometimes consuming a quart every 1,000 miles. This is commonly linked to a faulty PCV valve system and carbon buildup on the piston rings due to direct injection (DI) technology. DI engines lack fuel wash over the intake valves, leading to carbon deposits that prevent the rings from sealing properly.
  • Engine Stalling and Rough Idle: Many owners report random stalling events or a rough idle, often accompanied by a flashing check engine light. This is frequently caused by a malfunctioning Electronic Throttle Control (ETC) system or a failing crankshaft position sensor. In some cases, a software update is required to correct the calibration.

2.0L Turbocharged I4: The New Gen Learning Curve

The 2.0L turbocharged four-cylinder was introduced in the 2018 Wrangler JL and later other models. It offers strong torque, but its first year on the market was plagued with teething problems.

  • ESS (Engine Stop/Start) and Auxiliary Battery Failure: The 2.0L is heavily reliant on its electrical system. The auxiliary 12V battery powers the ESS system and the electronics during startup. This battery is notoriously weak. When it fails (which can happen as early as 12 months), the vehicle either won't start, will have a dead battery warning, or will display a "Service ESS" message. This is often misdiagnosed as a main battery issue.
  • Cooling System and Water Pump Failures: The 2.0L runs hot. The electric water pump and cooling system components are prone to early failure. A failing water pump often whines loudly, and the engine can overheat without warning if the pump seizes or leaks.
  • Excessive Oil Consumption (PCV/Turbo Seals): Like the Pentastar, the 2.0L can also consume oil. Here, the culprit is often a failing PCV valve or leaking turbocharger oil seals. Blue smoke from the exhaust is a clear indicator of these problems.
  • Hard Starting and Stalling: Similar to the Pentastar, but often worse in the 2.0T. Faulty high-pressure fuel pump (HPFP) and low-pressure fuel pump sensors can cause the engine to crank excessively before starting or to stall at low speeds.

5.7L and 6.4L HEMI V8: The Muscle Car Problems

Jeep's big-block offerings in the Grand Cherokee and Wrangler (392) are celebrated for power, but the 2018 models have distinct issues.

  • The HEMI Tick (Lifter Failure): The most notorious HEMI problem is the "tick." This is usually caused by a collapsed valve lifter, often due to contamination from metal debris or a failure of the MDS (Multi-Displacement System) solenoids. A bad lifter damages the camshaft lobe. If caught early, the lifter and camshaft can be replaced. If ignored, the entire engine may need to be rebuilt.
  • Broken Exhaust Manifold Bolts: The cast-iron exhaust manifolds on the HEMI expand and contract at a different rate than the aluminum cylinder heads. This causes the manifold bolts to snap. The result is a loud ticking noise on cold start that goes away after the engine warms up and the metal expands. This requires extracting the broken bolts (which can be very difficult) and replacing them with studs.
  • MDS System Failures: The MDS system deactivates four cylinders to save fuel. The solenoids and lifters associated with this system are failure-prone. Owners often notice a change in engine sound or vibration when the MDS activates or deactivates. A mechanical failure of the MDS system can lead to lifter collapse and camshaft damage.

Recognizing the Symptoms Early

Early detection is key to preventing extensive damage. Here are the specific symptoms to watch for in your 2018 Jeep:

  • Ticking or Knocking Sounds: A rhythmic tick that increases with RPM often points to a lifter or exhaust manifold issue. A deeper knock could indicate rod bearing damage from low oil pressure.
  • White or Blue Smoke from Exhaust: Blue smoke indicates burning oil. White smoke (especially a thick, sweet-smelling cloud) indicates a coolant leak, often from a failing oil cooler or head gasket.
  • Warning Lights: Do not ignore the check engine light. In the 2018 models, the system is sensitive to misfires and oil pressure drops. A flashing check engine light means a severe misfire that can damage the catalytic converter.
  • Oil Puddles Under the Vehicle: If you see oil on your driveway, check the top of the engine first. The Pentastar oil cooler housing sits high up, and leaks from it will drip down onto the exhaust and ground.
  • Reduced Fuel Economy: A sudden drop in fuel mileage is a strong indicator of a mechanical problem, such as a stuck open injector, a misfire, or dragging brakes, but often starts with an engine running inefficiently due to a sensor fault.

Manufacturer Recalls and Official Fixes

The manufacturer (now Stellantis) has issued several recalls to address the most safety-critical issues in the 2018 Jeep lineup. Owners should verify their VIN against the NHTSA database immediately.

Major Recalls for 2018 Jeep Models

  • Engine Stalling and ESS Failure (Wrangler JL): Recall S85. This recall addressed a software issue in the Powertrain Control Module (PCM) that could cause the engine to stall after restarting from an ESS event. The fix was a dealer reflash of the PCM software.
  • High-Pressure Fuel Pump Failure (Grand Cherokee/Cherokee): A recall for certain 2.0L and 3.6L engines regarding the high-pressure fuel pump. If the pump fails internally, it can contaminate the fuel system with metal debris, leading to engine stalling or a no-start condition.
  • Faulty Crankshaft Position Sensor (Multiple Models): A recall was issued for a batch of crankshaft position sensors that could fail prematurely, causing the engine to stall without warning. The fix is a replacement of the sensor.
  • Coolant Leak from Oil Cooler (Service Campaign): While not a formal safety recall, many dealers issued a "Customer Satisfaction Notification" to replace the plastic oil cooler housing with an updated part. Check with your dealer if this applies to your VIN.

Technical Service Bulletins (TSBs) Owners Should Know

If your vehicle is out of warranty, these TSBs provide the official repair procedures that independent shops can follow.

  • TSB 09-003-20 (3.6L Oil Consumption): This TSB outlines the diagnostic procedure for excessive oil consumption and, in many cases, authorizes the replacement of the pistons and piston rings with a revised design to reduce oil burning.
  • TSB 18-115-19 (3.6L Cylinder Head Replacement): This bulletin provides the guidelines for replacing the left bank cylinder head on the Pentastar engine if a misfire is diagnosed due to valve train failure.
  • TSB 23-006-21 (2.0L Stalling): This TSB addresses the repeated stalling of the 2.0L engine by updating the calibration of the PCM and Transmission Control Module (TCM).

Solutions and Repair Strategies

Whether you are a DIY owner or taking your Jeep to a shop, the repair strategy depends on the severity of the problem and the warranty status of your vehicle.

Dealer-Level Fixes (Warranty/Recall)

If your 2018 Jeep is still under the factory warranty or an extended MOPAR warranty, take it to the dealer. For the cylinder head issue, the dealer will replace the head assembly with a revised casting. For oil consumption, they will perform an oil consumption test and, if it fails, will replace the pistons and rings. For the HEMI tick, the standard procedure is to replace the lifters, camshaft, and potentially the MDS solenoids.

Aftermarket and Long-Term Fixes

For owners out of warranty, aftermarket solutions often provide a more permanent repair than the OEM parts.

  • Aluminum Oil Cooler Housing: This is the number one upgrade for the Pentastar V6. Replacing the factory plastic housing with an aluminum unit (from brands like Dorman) eliminates the risk of cracking and leaking. It costs roughly $150-200 instead of $600+ for a dealer repair.
  • Oil Catch Can: Installing an oil catch can on the PCV system of the 3.6L and 2.0L engines prevents oil vapor from coating the intake valves and piston rings. This is a strong preventative measure against carbon buildup and oil consumption.
  • MDS Delete Kit: For HEMI owners experiencing tick/valve train noise, a full MDS delete kit (which replaces the MDS lifters with standard lifters and blocks the oil passages) eliminates the root cause of the failure. This also requires a custom tune to disable the MDS in the ECU.

Preventative Maintenance

The 2018 Jeep models are sensitive to maintenance habits. Sticking to a strict schedule will save you thousands of dollars in repairs.

  • Oil Changes Every 5,000 Miles: Do not follow the 10,000-mile "severe service" interval. Change the oil and filter every 5,000 miles using a high-quality full synthetic oil (0W-20 or 5W-20 as recommended). This prevents sludge and keeps the variable valve timing solenoids and lifters working correctly.
  • Check the Auxiliary Battery: Replace the auxiliary battery proactively every 3 years. A failing aux battery can drain the main battery and cause a cascade of electrical problems. It is often located behind the main battery or in the wheel well.
  • Fuel System Cleaning: Because the 3.6L and 2.0L engines are direct injected, have the intake valves cleaned (media blasting) every 60,000-80,000 miles to remove carbon deposits. This restores fuel economy and power.

Frequently Asked Questions

Here are the answers to the most common questions owners have about the 2018 Jeep engines.

Are 2018 Jeep engines reliable?

The 2018 model year is considered a "transition" year. The engines themselves are fundamentally robust, but they have specific failure points (cylinder heads, oil coolers, lifters) that require attention. With diligent maintenance and the standard recall fixes applied, they can be very reliable for the long haul.

How much does it cost to fix a Pentastar tick?

If the tick is due to a collapsed lifter or cylinder head failure, a dealer repair can cost between $2,500 and $4,500. An independent shop performing the same work with aftermarket parts (aluminum oil cooler, upgraded lifters) can often do it for $1,500 to $2,500.

Is the 2.0L turbo better than the 3.6L Pentastar?

For fuel economy and low-end torque, the 2.0L is better. For long-term reliability and simplicity, the 3.6L Pentastar (with its recall fixes applied) is generally considered the safer choice. The 2.0L's reliance on a complex electrical system and a turbocharger introduces more potential failure points.

Does the warranty cover the HEMI tick?

Yes, if the vehicle is still under the factory powertrain warranty (5 years/60,000 miles for most U.S. models), a lifter failure and camshaft damage is a covered repair. If the warranty has expired, this is a very expensive repair (often $5,000+ at a dealer).

The Verdict on the 2018 Jeep Lineup

The 2018 Jeep models are among the most capable and desirable off-road vehicles on the used market. However, the engine problems described here are not minor annoyances; they are mechanical issues that require immediate attention to avoid catastrophic failure. The good news is that these problems are well-documented. The bad news is that they are expensive to fix if they are neglected.

If you are buying a used 2018 Jeep, check that the recalls have been completed and ask for proof of regular oil changes. If you already own one, proactive maintenance—especially replacing the oil cooler housing and installing a catch can—will significantly improve your ownership experience. These engines can last well over 200,000 miles, but they demand a more engaged owner than previous generations.

Additional Resources

To keep your vehicle safe and up to date: