Buying a Jeep often means big plans – a mountain trail, a beach, or just getting back and forth to work with a bit of extra fun in your car. Yet, there are a lot of options. How do you choose? One key thing to consider is the Jeep 4.0L engine.
What are the specs of the Jeep 4.0L engine?
The Jeep 4.0L engine is a 4.0L (241.6 ci) 6-cylinder engine. It has a 3.8-inch bore and 3.41-inch stroke with 12 overhead valves. This engine gets an 8.8-to-a compression ratio and produces 190 horsepower at 4600 RPMs and 235 lb-ft.
Before you buy any vehicle, you need to know all of the specs and features. Here, we’ll break down some of that info and provide you with the rundown of this model’s history. We’ll even answer some of the most common questions about this Jeep 4.0 engine.
What Is the History of the Jeep 4.0L Engine?
Let’s be frank. If you know your Jeep vehicles, you may know the Jeep 4.0L engine is one of the most well-recognized of the options. It was used in these vehicles from 1987 through 2006, and although not found in modern vehicles, you’ll still hear people talking about them.
Prior to the development of this engine for Jeep vehicles, the company used inline 6-cylinder engines for many years. That includes the Torque Command version put into use in 1964. It was noted in the Rambler Classic Typhoon.
In the coming years, the inline 6 engine saw a lot of changes. In 1972, AMC, the manufacturer of the Jeep at the time, created a bell housing bolt pattern that matched the ones used on V8s. This allowed for the Jeep CJ to be fitted with the 6 cylinder engine.
This design would be found on many vehicles from Jeep at that time. This includes the J-Series, Wagoneer, Cherokee, and Commando.
It wasn’t until 1986 that AMC would put the 4.0 into these vehicles. That’s when it created a 242 cubic inch engine – and by the way, they did this within just over two years. This engine improved the combustion chamber as well as the engine’s strength.
When Chrysler took over the lineup, it kept the Jeep 4.0L engine in place. That’s because, with its cam profile and port setup, it was a powerful and attractive option for consumers. Chrysler worked to refine the engine and continued to make changes to reduce vibration and noise.
In the coming years, this engine was used in numerous vehicles. That’s because it had a significant amount of torque. The long crankshaft allowed for this and, against many competitors, it really stood out.
In 2006, Jeep decided to discontinue the Jeep 4.0 engine. The next version, found in the Wrangler, featured a 3.8L (230.5 ci) OHV V6 engine. Chrysler designed this engine and used it most commonly in its minivan lineup. That did disappoint some loyal Jeep drivers.
Which Models Used the Jeep 4.0L Engine?
There are many vehicles over the years that used the Jeep 4.0L engines. However, these are the most notable of them:
- 1987 to 2001 Jeep Cherokee
- 1987 to 1992 Jeep Comanche
- 1987 to 1990 Jeep Wagoneer
- 1991 to 2006 Jeep Wrangler
- 1993 to 2004 Jeep Grand Cherokee
You can still find these engines discussed and rebuilt. People want to keep them around for their performance and just because they are a true Jeep engine and not a Chrysler minivan engine. No one wants to brag about off-roading in a minivan!
People Also Ask These Related Questions About the Jeep 4.0L Engine
Because they get a lot of attention, there are often many questions about the Jeep 4.0L engine. You can find some of those answers to common questions right here.
How Long Do Jeep 4.0L Engines Last?
The good news is that these are engines that do last. It’s not uncommon to find some lasting up to 150,000 miles. When well cared for and maintained, there are claims of these engines lasting over 200,000 miles. Off-roading and rough riding may reduce that.
Who Makes the Jeep 4.0L Engine?
The original Jeep 4.0L engine was made by AMC, the company that developed the Jeep and the inline 6 cylinder engine for it. However, Chrysler took over production of the Jeep 4.0L and continued to maintain it through 2006. They made refinements to it nearly annually.
How Much Boost Can a Stock Jeep 4.0L Handle?
While this depends on multiple factors, there are reports of these vehicles handling over 400 horsepower and more than 6000 RPMs. However, there are other factors that could go wrong including a cracked crankshaft rod.
How Much Horsepower Does A Jeep 4.0L High Output Have?
The AMC straight 6 engine has a power output of 129 to 200 horsepower or 96 to 149 kws and 131 to 203 PS. It also gets 216 to 280 lb-ft. or 293 to 380 N.M.
How Reliable Is the Jeep 4.0L Engine?
If you’re thinking about purchasing a vehicle with the Jeep 4.0L engine, you can expect it to have good reliability. It does not have a lot of recalls or problem components on it. That is one of the other reasons that Jeep lovers enjoyed this engine – it didn’t fail them often.
What Made Jeep 4.0L Engines So Good?
There are many people that claim these engines are some of the best ever designed by Jeep. That’s because they have materials that last and the bore and stroke are over square. It really offers superior handling and power for these vehicles as well.
Should You Buy a Vehicle with a Jeep 4.0L Engine in It?
For those that love the classic Jeep and want to keep it going, the Jeep 4.0L engine is a solid buy. It may be hard to find if you’re looking for parts, but this engine may still be available on that pre-owned Wrangler dating back to the early 2000s.
