Understanding The Common Jeep 3.8 Engine Problems and How to Fix Them

The Chrysler 3.8 was introduced in 1991, It remained a popular engine in many Jeep models for 20 years.

If you are looking at a used Jeep that has a 3.8 engine in it you are looking at a fairly reliable engine that can last for more than 400,000 miles with proper maintenance and care.

Common Jeep 3.8 Engine problems and Fixes 

Jeep 3.8 Engine

The Jeep 3.8 by Chrysler is a good engine but nothing is perfect so it does have a few problems that owners complain of.

Problem #1

Excessive oil use and oil leaks

The jury is out on whether this is the number one problem with the Jeep 3.8 engine. We do however know for a fact that many Jeep owners have complained about their 3.8 engines using more oil than they thought was normal.

This engine uses 5.9 quarts of oil at fill-up time. When you check your oil and the dipstick shows that you need to add oil you will need to add one quart if the oil line is on the add mark.

If the oil on the dipstick is below the add mark you should start by pouring one quart of oil into the engine. Then check the oil level again and add more as needed. As you add more oil you should add it one-half of a quart at a time and check after each addition.

Remember that putting too much engine oil in the engine is just as bad, if not worse than letting the engine be low on oil.

Signs that the vehicle is using high amounts of oil

  • When the engine is running you may see smoke coming from the exhaust
  • You might smell burning oil
  • Your check engine light might illuminate on the dash
  • You might have low engine oil levels when you check your oil
  • You might hear some knocking or pinging noises

What to do

If your Jeep 3.8 is using more engine oil than you think is normal the first thing you should do is check to see if you have any oil leaks. If you find a leak you can stop it and stop the oil usage.

You can try putting a higher viscosity oil in the engine. When choosing an engine oil with a heavier viscosity keep in mind the heaviest viscosity that Chrysler recommends for the 3.8 and do not go above that viscosity.

If the engine is using more than one quart of oil for every 1,000 miles of travel you need to go ahead and let a certified technician evaluate the problem.

Problem #2

A knocking sound when you first crank the vehicle

A knocking sound when you crank the engine could be a minor problem but then again it could also indicate some serious issues. 

After 100,000 miles have been put on the vehicle most owners expect to start hearing some unusual noises, pings, and knocking sounds.

What to do:

The first course of action must be to have the vehicle placed on a diagnostic machine at a certified repair shop to see what is causing this unusual noise.

Some people say that they replaced their oil filter with a Mopar oil filter and the knocking in their engines was solved.

We still recommend you seek the advice of a certified technician if you hear any knocking sounds coming from your engine.

Problem #3

Leaks in the Intake Manifold

Intake Manifold

This problem seems to be most common in the 2001 Jeep 3.8 engines.

On average, a vehicle will travel about 100,000 miles before it has an issue with leaks in the intake manifold. The Jeep 3.8 that was used in 2001 vehicles has a tendency to have this issue a lot faster than 100,000 miles.

Some signs of this problem are

  • Low levels of engine coolant
  • The manifold may start to crack 
  • The transmission bell may be damp
  • You may see steam being emitted from the engine bay
  • A loss of power when you accelerate
  • You may use more fuel than normal
  • Your engine may stall

How serious is this problem?

This problem can be very serious. Over time if it is not corrected it can cause engine rust to form and even cause the engine to stop running.

What to do

The only real course of action is for you to change the intake manifold gasket.

This can be a very involved task and most people opt to take the vehicle to a repair shop and have them change the gasket for them.

A mechanic can usually do this work in just a couple of hours. The price of the repairs will only be about $300 dollars or less.

Problem #4

Engine Rust and Corrosion

Rust formation on various engine components is commonly complained about by people who have a Jeep 3.8.

Rusting parts is irritating and eventually, the parts can stop functioning properly because of the rust and corrosion on the different components. The parts cannot work smoothly because the rust stops them from moving freely.

What to do?

The only real solution to the formation of rust and corrosion is to use an anti-rust solution to protect your parts and reduce the amount of corrosion that builds upon them.


Who Manufactures The Jeep 3.8 L Engine?

Chrysler Corporation manufactures these engines.

Is The Jeep 3.8 Better Than The 3.3 V6?

Yes, it is. The 3.8 has a wider bore and a longer stroke than the 3.3 had. The 3.8 is a solid engine that has been a good performance from the beginning.

How Many Miles Can You Get Out of A 3.8?

The average Jeep 3.8 can last up to 400,000 miles with proper maintenance and care. 

Final Thoughts

The 3.8 Jeep engine offers solid performance and reliability. You must keep the maintenance done on the engine, and you have to pay attention to little warning signs so you can fix problems before they become major issues.

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