The 3 Most Common Jeep Liberty 3.7L Engine Problems

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No matter the amount of money invested or time expended, all machines must develop a fault.

Sometimes it comes at a small scale and can be fixed by little maintenance; at other times, the damage can permanently shut down the machine. Like every machine, the Jeep Liberty 3.7 Engine problems also manifest in a number of ways.

The most common issues associated with the Jeep Liberty 3.7 engine are:

  1. Valve Seal Failures
  2. Defective Piston Ring Landing
  3. Positive Crankcase Ventilation (PCV) Valve Problems

You may not understand the depth of the issues your Jeep Liberty 3.7 engine will produce if you don’t pay close attention to them. Different models of the Jeep Liberty engine function optimally, but they can become frail and damaged like every other machine.

What Are The Most Common Jeep Liberty 3.7L Engine Issues?

1. Valve Seal Failures

Failure of valve seals is one of the common Jeep Liberty 3.7 Engine problems. The Jeep Liberty is famed for being one of the most reliable midsized SUVs.

The valve seal in the internal combustion engine is the surface where the intake or the exhaust valve rests when the engine is active. This seal allows and restricts airflow in the valve but it is most important to maintain cylinder compression.

Because the seals are made from powdered metal, they can enlarge or wear out due to long use. When the valve seals fail, it simultaneously causes the airtight seal of cylinders to break, causing loss of compression within the cylinder.

Loss of compression by cylinder will result in a decrease in the production of power by the engine, which is necessary to move the pistons and crankshaft. Failure of these parts to move will cause the car to become immobile.

What To Look For

When a valve seal fails in the Jeep Liberty 3.7 engine, most of the time, only a cylinder is affected. This can make it very difficult to spot the problem.

Nonetheless, the following signs are some of the effects of a failed valve seal:

  • Loss Of Acceleration: When the valve seals are damaged, the rate at which a car can increase its speed is drastically reduced.
  • Cold Engine: It’s one of the earliest and easiest signs of a bad valve seal failure. When you parked outdoors overnight, and, on inspection the following morning, you found some residual oil on the cylinder’s head located in the valve seal. There’s a chance that the valve seal is faulty, worn or damaged.
    Alternatively, when the engine is idling and you see some residual oil dripping down the combustion chamber through the faulty valve cover, then, it’s time to change the seal. This will be followed by a bluish smoke that comes off the tailpipe.
  • Cylinder Misfires: It is the incomplete or zero combustion in a cylinder. This is one of the most common symptoms that will alert you to valve seal failure.
    When a misfiring car is being driven, the driver experiences the feeling of hesitation or shaking of the automobile. Since it can only be caused by bad plugs or ignition coils and failed vale seals, it can easily be narrowed down.
  • Loss Of Power: When the engine starts to lose power, it is easily noticeable by the driver. When the accelerator is stepped on when driving, the engine fails to respond.
  • Engine Idle: When a valve seal breaks, you may also notice that at stop signs, your car will start to idle for an extended period. The reason is basically that the intake manifold is housing an excessive amount of vacuum due to the closed status of the throttle valve. The closed valve causes oil to drip into the heads.

What To Do

When valve sets fail, they are usually severally damaged and cannot be fixed. You will have to replace them. If you have DIY knowledge on how to get the seals replaced and have the right tools, you can save costs.

With a variety of techniques, valve seals can be removed in the comfort of your own garage. You can replace the valve guide oil seals by either removing the cylinder head or without removing it.

Either way, the steps are simple and the process convenient. Like earlier noted, faulty valve seals can cause your engine to idle and gives off blue smoke.

Procedure 1: Replacing Valve Seal by Removing The cylinder Head

Step 1:

  1. Disengage the engine to have access to the valve spring.
  2. Remove the cylinder head.
  3. Detach the rocker arms, spark plugs, and pushrods.
  4. Regulate the air to between 60-90psi by turning on the air compressor.
  5. Spin the crankshaft to make sure the cylinder with the faulty valve seals comes to the center.
  6. Tighten the compression scale hose firmly into the spark plug hole.
  7. Fasten the air compressor hose to enable the cylinder to receive enough pressure.

Step 2

As long as the cylinder is air-pressurized, the valves will remain in a closed position.

You can now complete the rest of the process:

  1. Compress the valve spring with the valve spring tool.
  2. Using a magnet, remove the valve spring keepers.
  3. Surround the area with a towel to avoid the valve springs dropping into the tight part of the engine.
  4. Use a pair of pliers to disconnect the faulty valve seal and replace it with a new one.
  5. Replace all loosened parts of the engine and couple the engine back.
Procedure 2: Replacing Valve Seals Without Removing A Cylinder Head
  1. Unscrew the air cleaner to access the valve seal.
  2. With a wrench, disconnect the ground battery cable.
  3. Use the socket, ratchet, and ratchet extension to removes the valve cover.
  4. Pull off the wires connected to the spark plugs.
  5. Clean the surrounding of the spark plugs.
  6. Rotate the crankshaft bolt slowly in a clockwise twist with a ratchet.
  7. Take off the rocker arm and slowly release the valve spring compressor to take off the valve washer and valve spring.
  8. Replace the rocker arm.

The good news is that you won’t have to spend much to replace a broken or damaged valve seal. The labour cost of replacing defective valve seals is between $220 and $278 while the parts cost about $26 and $58. The prices vary from mechanic to mechanic.

2. Defective Piston Ring Landing

As in all other cars in the Jeep Liberty 3.7 Engine, the piston ringlands have two parallel surfaces in the groove of the piston rings. They function as the sealing surface of the piston rings in connection with the cylinder wall.

Together with the piston grooves, the piston lands seal the piston against the cylinder wall. They hold an airtight seal over the cylinder wall.

By design, the Jeep Liberty 3.7 engine pistons, -like turbocharged 2.0l and 2.5l engines- comes with three ringlands located adjacent to the rings and ring grooves.

The ring lands house one oil control ring and two compression rings. Typically, piston ring land failures are caused by detonation, which in turn is triggered by a lack of proper tuning, low octane fuel, and extended hard driving.

Detonation occurs when there is an automatic ignition that produces flame fronts in the combustion chamber; these flames cause excessive pressure spike that affects the cylinder walls, forcing the formation of cyclical load.

Due to a flaw in the design of the Jeep Liberty 3.7 engine, the piston ring lands produce excessive heat which causes the engine to run hotter than it should be.

The overheating problem was escalated by another design flaw in the oil drain holes of the Jeep Liberty 3.7 engine. The holes were made too small, which causes heat to be retained in the engine.

Because lubrication oil does not fare well with excessive heat, it is broken down from the engine into sludge and blocks it. Fresh oil cannot move you around where it is needed. If the problem is not rectified immediately, engine damage occurs due to oil starvation, overheating, and engine seizure.

In the worst-case scenario, when the engine gets to the point of seizure, a repair would be impossible. The engine will have to be replaced or rebuilt.

What To Look For

The overall effect of defective piston ring lands of the Jeep Liberty 3.7 engine is overheating.

Some of the visible effects that will inform you of this problem are:

  • Coolant Leakage: When overwhelming occurs, cooling systems such as the radiators, hoses and all others might start developing leaks, leading to coolant leakage. As more coolant leaks out of the engine, there is an exponential increase in the heat build-up of the engine.
  • Excess Oil Consumption: As heat builds up it’s the engine from the defective piston rings and small oil drain holes, oil burns more quickly. This will cause an increase in friction of the internal components of the engine due to a lack of lubrication.
  • Stuck Lash Adjusters: Because of the sludge that accumulates from the overheating of lubrication oil, the lash adjusters become stuck. When this is noticed, it is a sure sign that the piston rings are defective.

What To Do

Unfortunately, this problem is because of an engine design flaw from the company so there is nothing you can really do about it.

Overheating of the engine can be prevented by using only light oils on the engine and constantly changing the bad oil.

How To Prevent Pistons Ring Lands Failures

Since fixing the pistons ringlands are impossible, the best procedure is to prevent damage to the components.

Here are precautionary measures to take:

  • Improve Exhaust Flow: The Jeep Liberty 3.7 engine cylinder usually runs hotter due to reduced port flow velocity and rear pressure. Allowing exhaust free flow of exhaust causes the back pressure to expel hot and excess gas while enhancing the engine efficiency.
  • Reduce Intake Air Temperatures: There are two things you can do to reduce the intake air temperature. One way is to run the plastic stock airbox. The insulated, sealed airbox is designed essentially to get rid of excessive airflow into the grill duct.
    Alternatively, you can reduce the temperatures of the underhood by properly ventilating the hoods with a thermal insulator around the thermal tape, turbo blanket, and exhaust parts.
  • Eliminate Oil Vapour Ingestion: As you ensure reduction of intake air temperatures, don’t forget to also look into reducing oil vapour ingestion. You can achieve this by keeping the intake track surrounding clean while getting rid of oil vapour that settles in the tract.
    Simply run an air-fuel separator or catch can. But because the Jeep Liberty 3.7 is a horizontal engine, you may experience a breather flow or fuel blow-by.
  • Ensure High Octane Fuel: Going for a recommended, high-grade gasoline is a no-brainer. Make sure the tune also gets proper octane fuel.
  • Use Ethanol-Based Fuel: High boosted engines like Jeep Liberty 3.7 should operate alcohol-based (methanol and ethanol) flex fuels.
    Because of their heat properties, these types of fuels have a built-in mechanism that helps to cool incoming engine-bound air. They also have a high resistance to detonation, thanks to their low sensitivity.

Other preventive measures against pistons ringland damage include listening to the feedback knock from the engine, and a regular running of a catch can.

3. Positive Crankcase Ventilation (PCV) Valve Problems

Jeep Liberty 3.7 engine problems the PCV valve is responsible for ejecting waste gas that accumulates in the crankcase of the engine.

These are gases that were not ejected by the exhaust and got trapped in the crankcase that holds oil at the bottom of the engine. The PCV valve is attached to this crankcase and it releases these gases.

In the Jeep Liberty 3.7 engine, the valve can become clogged and when it happens, the oil in the crankcase is damaged and becomes like sludge. This will lead to oil leaks throughout the engine.

What To Look For

Although the positive crankcase ventilation valve problem might look insignificant, it has major effects.

  • Rough Idle: Rough idling is experienced by the driver when the PCV valve is damaged. It is an identifiable sensation of shaking or bouncing while driving. Odd sounds along with inconsistent RPMs can also be noticed.
  • Engine Hesitation: It is characterized by misfiring of an engine or, stumbling or lack of power of a car when the driver wants to accelerate.
  • Oil Leaks: As stated earlier in the article, after the crankcase was damaged by sludge oil, leaks began to occur throughout the engine.
  • High Oil Consumption: A damaged PCV valve will cause you to visit the gas station more often than usual due to the excessive fuel consumption it causes. Due to increased pressure in the crankcase, the PCV valve might fail to work, causing the oil to escape through the gaskets and caps.

What To Do

If you are sure that the PCV valve has been damaged, rest assured because replacing it is relatively cheap and it is not quite as hard to fix. Before a new valve is installed all the old oil has to be flushed out.

If you notice that the hose is brittle, sledge-filled, soft, springy, dry, or full of hard deposits, it’s time to replace it. The clamps may be rusty causing the PCV not to function effectively.

Follow these steps to get your PCV replaced:

  1. Unscrew the tube clamp.
  2. Remove the valve.
  3. Remove the duct and send some air through it.
  4. Reassemble the hose to the PCV.

The cost of the valve is about $15 but you can save some cost if you have appropriate knowledge about fixing it. If not, call your mechanic.

How Does Jeep Liberty 3.7 Engine Fair?

Although the engine has a lot of design errors, the most prominent include the piston ring lands and oil escape holes. Otherwise, the Jeep Liberty 3.7 engine is a very good engine. It provides plenty of torque so it is very useful for off-road use. The engine also packs enough power for towing.

Another downside of the 3.7 engine is its acceleration. When you are driving on the street or expressway, and you want to accelerate, it is noticeably slow.

The Jeep Liberty 3.7 engine can last 200,000 to 300,000 miles. Like all engines, when maintained the engine can run at an optimal rate, free of problems.


1. Is The Jeep Liberty 3.7 Engine Reliable?

While the engine comes with its own shortcomings, it is a very reliable and durable engine. With proper maintenance, the engine life span extends to 200,000 miles. Constant monitoring of the engine’s timing chain and crankcase ventilation system will definitely enable you to get the most out of the engine.

2. What Are The Specs For The Jeep Liberty 3.7 Engine?

Features: Specs:
Number Of Cylinders 6
Fuel Type Gasoline
Configuration V
Horsepower 210
Valves Per Cylinder 2
Fuel System Sequential Fuel Injection

Final Thoughts

Each engine has problems common to them but that does not mean that they are incapable of good performance. The Jeep Liberty 3.7 engine is no different.

The engine has problems associated with its design that could potentially reduce its lifespan. But with proper and prompt maintenance and care, you can be sure of getting the best out of this engine.