Is Your Jeep Wrangler Overheating? Here Are 10 Reasons (& Fixes)

One of the most common reasons that many owners find themselves heading to the mechanic is to know why is their Jeep Wrangler overheating. Unfortunately, there’s not one clear problem that makes a Jeep Wrangler overheat.

This means that either you or your mechanic will need to do some investigating to find the exact cause of why your Jeep Wrangler is overheating.

The most common issues that cause a Jeep Wrangler to overheat are low coolant levels or a faulty part, such as the cooling system, radiator, thermostat, water pump, heater core, head gasket, or blower motor resistor.

In most cases, the problem can be solved by finding and replacing the faulty part. Depending on the complexity, it’s a job that you can do by yourself.

When it comes to any car problem, the biggest hurdle is often just determining what the issue even is in order to fix it.

So, is your Jeep Wrangler overhating? Let’s go through the 10 reasons that can cause a Jeep Wrangler to overheat as well as how to fix them so that you can get your Jeep up and running like normal again.

What Are Common Causes of Overheating in a Jeep Wrangler?

Unfortunately, there’s more than one issue that could potentially be causing your Jeep Wrangler to overheat. Let’s go through ten of the most common things that could cause this problem.

If you find your Jeep Wrangler overheating, these ten possibilities are the best way to weed out the problems. They’re listed in order of difficulty in diagnosing, with the first being the easiest to diagnose. However, their level of complexity when fixing could vary depending on your car.

1. Faulty Radiator

This cause is one of the simplest ones to understand if you come across your Jeep Wrangler overheating. If your radiator is failing, then your fans are likely failing as well.

To figure out if this is the problem with your vehicle, begin by looking at your radiator cap. If there’s no pressure coming from the cap, then your Wrangler is likely overheating due to a faulty radiator cap causing your fans to fail. This cap is important as it uses pressure to get coolant into your radiator.

To fix this problem, you simply need to replace your radiator cap. If you don’t see any drops in coolant temperature once the cap is replaced, the source of your Jeep Wrangler overheating problem is likely elsewhere.

Even so, we always recommend that, if your radiator cap is old, changing it is a good practice.

2. Faulty Thermostat

This is another relatively simple potential cause. Just like a regular thermostat in your home, the thermostat in your Wrangler is in charge of reading the temperature of your Jeep’s engine. Once the thermostat detects that your Jeep is overheating, it sends a signal that coolant should be released.

However, if your thermostat is faulty, then this signal for coolant is never given. This leads to your Jeep’s engine reaching extremely high temperatures and overheating.

If your Jeep’s thermostat is faulty, then you simply need to get it fixed or replaced. So, how do you test a thermostat?

There’s an easy test to do, called the “hose test”, and here are the steps:

• First, you must ensure the engine is completely cold. So, early morning tests are better.
• Start the car and let it idle. This should increase the engine’s temperature.
• Put your hand on the upper radiator hose. If your thermostat is working properly, then the hose will be cool at first, then suddenly it gets hot, because the thermostat opens.
• If your hose warms up slowly but right away, then your thermostat is stuck-open. This means it’s not regulating flow.
• If your hose is cold and the engine is warming up, the thermostat is stuck-closed, meaning there’s no coolant flow at all (or very little).
• If any of these happen, you should change your thermostat.

3. Faulty Water Pump

The water pump is the part of your Jeep that’s responsible for controlling the flow of coolant in your Jeep’s system. This means that if your Jeep has a faulty water pump, your system likely isn’t getting enough coolant and can be susceptible to overheating.

Let’s say you find your Jeep Wrangler overheating all of a sudden. This is a typical symptom of a faulty pump. There are some people that say you should test a pump by opening the radiator cap to see if coolant is flowing. This can help you diagnose a faulty pump, but be careful.

If your pump is fine, but the thermostat isn’t, coolant will gush out once you open the cap. Before doing this test, which should be done with a cold car, you should check the pump physically.

Pumps have weep holes. If these are crusty or leaking, the pump might be bad. Also, if the pump is lose, it could be another indicator that it’s bad.

4. Low Coolant

In the above potential causes, we saw a few things that could stop your system from delivering the proper amount of coolant. However, the number one thing that can prevent your system from getting enough coolant is if it simply doesn’t have any coolant to deliver!

In this case, the first thing you need to check are your coolant levels. If the levels are fine, check the coolant bottle for any holes that coolant could be leaking from. Most coolant holes, especially in older cars, are made of plastic that can crack easily, leaving you and your Jeep Wrangler overheating.

Also make sure that you’re using the recommended coolant for your Jeep. It should be listed on the inside of your engine’s cap.

5. Cooling System Airlock

Cooling system airlock is something that happens when your cooling system doesn’t have enough coolant.

Because there isn’t enough coolant, air is pumped through your cooling system, creating air pockets (or airlocks) in your cooling system and hindering the system’s ability to move coolant through the vehicle. This can also be caused by poor pressure levels in the cooling system.

To prevent this during servicing, you will want to “burp” your radiator as you fill it with coolant. You squeeze the large thick hose going from the radiator to the engine. You are forcing the air out and getting the coolant flowing properly from the radiator to the engine. Doing this will prevent air from getting trapped in your cooling system in most cases.

6. Low Airflow

The way coolant works is that it’s a liquid that is spread on the hotter parts of your car and then it cools when exposed to air. This means that if air can’t get to your radiator, your coolant will get to the radiator, but it will remain at a standard temperature rather than cooling it down.

To fix this, make sure your radiator has enough space around it for air to flow. Things that can block this airflow are modifications that block your Jeep’s grill or even leaves and dirt. Moving these should allow for proper airflow to cool down your coolant, and it should stop your Jeep Wrangler overheating.

7. Faulty Head Gasket

One of the most common things that can go wrong in your coolant system is a blown head gasket. This will cause coolant to leak into your system, which will lower your coolant levels and cause your system to overheat.

All you have to do to fix this is replace the head gasket. Do this as soon as possible as a blown head gasket can cause serious damage if it’s not fixed as soon as possible.

8. Low Oil Levels

This is one of the less common things that can cause overheating problems on your Jeep Wrangler, but it’s still entirely possible that this is the cause of your Jeep’s problems.

Motor oil lubes up your engine’s components in order to minimize friction. However, if your Jeep doesn’t have enough oil, then your motors parts will be rubbing against each other and generating massive amounts of heat.

To determine if this is the problem, all you have to do is check your oil levels. This should be something you check regularly anyways as driving in any vehicle without the proper amount of oil can cause serious damage to the engine.

9. Dysfunctional Heater Core

A dysfunctional heater core alone is more likely to cause issues with your car’s air conditioning rather than overheating in the engine.

However, combined with one of the problems listed above, a dysfunctional heater core could be the thing that pushes your Jeep’s engine over the edge into overheating territory.

To fix this, first make sure that any old or stale coolant is removed from your system by performing a heater core flush. If that doesn’t work, you may need to replace your heater core.

10. Faulty Blower Motor Resistor

A faulty blower motor resistor is another common issue that can leave your Jeep Wrangler overheating. This is one of the easiest problems to identify as well.

If your blower motor resistor is failing, you’ll likely hear strange noises coming from the blower, a burning smell will likely be coming from your air vents, and you’ll feel no air from those same vents.

To fix this issue, you may need to replace your blower motor, but first make sure to change your air filters. You should also inspect the fan belt if your Jeep has one and make sure it’s not snapped or trapped on something.

How to Prevent Your Jeep Wrangler From Overheating

The most common issue that can cause a Jeep Wrangler (or any car for that matter) to overheat is some sort of coolant leak. This shouldn’t come as a surprise since preventing the vehicle from overheating is the coolant’s job.

So, make sure to check your coolant levels regularly. If your coolant levels are dropping rapidly, there’s likely a leak somewhere in your coolant system that needs to be repaired.

The second most common issue that causes Jeep Wranglers to overheat is a fault in the radiator fan. To fix this problem, get a mechanic to inspect your radiator fan. In the worst case scenario, you may need to replace the fan entirely.