Jeep 4.0L Oil Capacity And Type Guide

The Jeep 4.0L is a popular choice among off-road enthusiasts, despite being discounted back in 2006 – mainly due to its easy maintenance and reliability.

But this reliability can’t be attained without proper know-how about its oil capacity and type, as these factors play a vital role in any engine’s performance and longevity.

Today, we’ll cover both of these issues in detail.

Jeep 4.0L Engine Overview

The 4.0L is a six-cylinder, in-line engine first introduced by AMC (American Motors Corporation) in 1986.

After buying out AMC in 1987, Chrysler continued to feature this engine until 2006 in different Jeep vehicles, such as Wrangler, Cherokee, Grand Cherokee, etc., with different upgrades after every few versions.

The upgrades mainly included higher flowing fuel injectors (1988), multi-port fuel injection and larger throttle body (1991), stronger engine block (1996), and distributor-less coil on plug ignition system (2000).

Below is the list of vehicles to come with a 4.0L engine;

• Jeep Cherokee (XJ): 1987-2001
• Jeep Comanche: 1987-1992
• Jeep Wagoneer: 1987-1990
• Jeep Wrangler (YJ, TJ): 1991-2006
• Jeep Grand Cherokee (ZJ, WJ): 1993-2004

Horsepower and Torque

The original RENIX 4.0L engines had 177 hp horsepower @ 4500 RPM and 220 lb-ft torque @ 2500 RPM.

In 1991, Chrysler replaced the RENIX system with multi-port fuel injection, enlarged the throttle body, and redesigned the intake and exhaust manifolds. These changes increased the horsepower and torque to 190 hp @ 4750 rpm and 225 lb-ft @ 4000 RPM.

The next major upgrades happened in 1996 and 2001, but the horsepower and torque remained almost the same, with 190 hp @ 4600 RPM and 225/235 lb-ft @ 3000/3200 RPM.

The Good

The primary reason for Jeep 4.0L’s popularity is its high low-end torque, which helps it in quick acceleration, off-roading (rock climbing, steep inclines, etc.), and towing.

Its simplicity and reliability are also worth mentioning. It comes with a simple design and fewer complex components, reducing the risk of malfunctions.

This design and durable build materials enable the 4.0L to have an extended lifespan. I personally know many people who went past the 300K-mile mark with it.

But even if you get any common engine issue, the 4.0L is pretty easy to diagnose, and its layout allows easier access to internal components.

Moreover, its aftermarket parts are relatively affordable due to 4.0L being in production for a long time, making maintenance much easier.

The Bad

The main downside of the 4.0L is that it’s an older engine.

It’s based on an older design and doesn’t have many features we get in newer engines, such as variable valve timing, variable valve lift, direct injection, turbocharging, etc.

The lack of these features was causing the 4.0L to have poor fuel economy and higher emissions.

These issues caused Chrysler to discontinue the Jeep 4.0L engine in Grand Cherokees after 2004. And in Jeep Wrangler models after 2006.

What’s The Jeep 4.0 Oil Capacity?

Like other vehicle engines, the Jeep 4.0L requires engine oil to act as a protective layer for many of its internal parts.

Apart from lubrication, it also acts as a coolant by preventing the engine from overheating and as a cleaning agent by keeping the engine clean from sludge, deposits, and contaminants.

When a vehicle leaves the factory, its engine oil is at full capacity.

But then it starts to decrease with time due to various factors, such as weak or damaged gaskets/seals (in older engines), evaporation at higher operating temperatures, oil burning, etc.

In such cases, you need to check the oil level with a dipstick and add/replace oil if necessary.

“But how much oil?,” you might ask.

It’s a valid question, as too little engine oil will lead to insufficient lubrication, engine overheating, reduced engine performance, etc.

Similarly, too much engine oil will increase stress on seals/gaskets, lead to oil foaming and spills, and potentially damage the catalytic converter.

Thankfully, every manufacturer lists the oil capacity of their vehicle’s engine in the owner’s manual.

For Jeep 4.0L engines, this capacity is 6 quarts which roughly equals 5.7 liters. It means if the oil pan is empty, you’ll have to put 6 quarts of new oil into the engine to refill it completely.

What is the Suitable Oil Type for Jeep 4.0L?

The next thing you need to determine is the correct oil type for your engine.

While the Jeep 4.0L is compatible with conventional and synthetic motor oils, you must also consider oil viscosity.

The engine oil viscosity determines how thick or thin the oil will be at different temperatures.

The viscosity ratings of engine oils are written in this format:
[oil viscosity at 0°F] W – [oil viscosity at 212°F]

The most common examples of viscosity ratings are 5w-20, 10w-30, 15w-40, 20w-40, etc.

When it comes to Jeep 4.0L vehicles, you get two options. If the temperature in your area varies between hot and cold, you should go with the 10w-30 oil.

But if you drive in an area with cold weather most of the year, the 5w-30 oil would be better. It has less cold-start viscosity than the 10w-30 oil, which allows it to flow between engine components more easily.

Check out this table to better understand the oil capacity and type for Jeep 4.0L vehicles.

Model	Year	Oil Capacity	Viscosity
Jeep Cherokee XJ	1987-1990	5.5 quarts (filter included)	10W-30/5W-30
Jeep Cherokee XJ	1991-1999	6 quarts (filter included)	10W-30/5W-30
Jeep Cherokee XJ	2000-2001	6 quarts (filter included)	10W-30/5W-30
Jeep Grand Cherokee ZJ	1993-1998	6 quarts (filter included)	10W-30/5W-30
Jeep Grand Cherokee WJ	1999-2004	6 quarts (filter included)	10W-30/5W-30
Jeep Wrangler YJ	1991-1995	6 quarts (filter included)	10W-30/5W-30
Jeep Wrangler TJ/LJ	1997-1999	6 quarts (filter included)	10W-30/5W-30
Jeep Wrangler TJ/LJ	2000-2006	6 quarts (filter included)	10W-30/5W-30

How to Change the Oil for Jeep 4.0L?

If you’ve checked your engine oil with a dipstick and found it to be low/dirty, it’s time to replace it.

Here’s what you need to do:

1. Drain the Older Oil

• Locate the oil drain plug. It’s usually found on the bottom of the oil pan.
• Place a drain pan directly below the oil pan.
• Loosen the plug with a socket set or wrench, and remove it. This will allow the older oil to drain out of the engine.
• You may have to adjust the drain pan position as the oil drains faster at first and slowly later.
• You can also use multiple pans to avoid oil spilling on the floor.

2. Replace the Oil Filter

• Locate the oil filter and loosen it up with an oil filter plier or wrench.
• Put a drain pan underneath when removing the filter, as it’ll contain some oil that can spill onto the floor.
• Lubricate the new oil filter’s seals with some new oil, put some oil into the filter itself, and attach it tightly to the old filter’s place.

3. Add New Oil

• By this time, the old oil would’ve been fully drained from your engine.
• Clean the drain plug and reinstall it. Make sure it’s tight, as you may have leaks otherwise.
• Remove the oil filler cap, put a funnel on the oil fill hole, and add 6 quarts of new oil into the engine.
• Once you’ve filled all the oil, wipe any spills or drips from the engine, and reinstall the fil cap.

Conclusion

Having the correct information about oil capacity and type is a critical part of any engine’s maintenance.

While the 4.0L is a reliable engine and doesn’t need much maintenance, you can’t be careless about the oil.

By adhering to the abovementioned guidelines properly, you can keep it well-lubricated and cooler, further extending its longevity and efficiency.

Frequently Asked Questions