Jeep Won't Start When Hot: Reasons, Symptoms & Solutions

When you see your jeep is overheating, that might lead to the jeep not starting. There can be several reasons for this to take place, but before fixing it, you need to diagnose the system first to detect the real issue.

So, what are the possible causes and solutions for Jeep won’t start when hot?

Starter issues arise on jeep wrangler JK due to internal default, a damaged spark plug creates an overheating problem in the jeep wrangler, and a fuel injection problem arises in the jeep liberty and grand Cherokee for clogged or damaged fuel injection. Other than these, battery problems can also cause overheating and the jeep won’t start.

If you want to know more about this is the right place for that.

Jeep Won’t Start When Hot: Reasons And Solutions

Here are the common problems for Jeep won’t start when hot according to the particular jeep models along with possible reasons, and the simplest solution.

Problem	Reason	Solution	Model
Starter Issue	Blown fuse Lack of power in ignition switch Worn wiring	Replace the fuse or wiring Replace the starter	Jeep Wrangler JK
Damaged Spark Plug	Driving at low speed for longer Dirty fuel injector Dirty air filter	Fix the spark damaged plugs Replace the spark plugs	Jeep Wrangler
Dirty fuel injector	Old fuel or carbon residue inside the fuel injector Fuel can’t go through the injector	Clean the clogged fuel injector. Replace the damaged injector	Jeep Liberty, Grand Cherokee, and Jeep wrangler
Battery Issue	Battery is old Worn electrical connection inside the battery	Jump start the battery Replace the battery	Jeep Wrangler JK
Corroded Battery Cable	Electrolyte emission from the top of the battery Excessive hydrogen gas emission from battery	Clean the corroded terminals Look for wear and tear for fixing Replace the battery terminals	Jeep XJ

Reason 1: Starter Issue

Blown fuse, lack of power in the ignition switch, worn wiring are the primary causes for making the starter extremely hot. As the starter is located right beside the motor, the heat of the starter is transmitted to the motor. As a result, the hot engine is even hotter.

This extremely hot starter doesn’t let the electricity flow to the engine and the engine fails to start.

Symptoms:

If you notice something unusual like a jeep starts immediately when it is cold. It is a clear indication of the starter problem for your jeep. Other than that, you will only notice the clicking noise, which is different from the cracking noise from the engine.

Solutions:

Usually, the starter issue ends when you replace the starter. Here are the required tools and steps for replacing your jeep starter-

Necessary Tools:

New starter
Wrench (Socket)
Extension cord

Replacement Steps:

At first, disconnect the negative battery cables so that there is no source of electricity in the system.
Make sure you detect the exact place of the starter. Typically it is located at the bottom or at the side of the engine.
Secondly, after the detection, disconnect the wires that attach the starter to the vehicle. There will be two wires, positive and negative.
Thirdly, use the wrench to loosen the bolts that are holding the wires tightly.
Forthly, install the new starter and connect the wires correctly.
For a regular starter, the positive wire will connect to the top and the negative to the bottom terminal.
Next, reconnect the battery cables starting with the negative.
Finally, tighten the bolts and wires using the socket wrench.

Particularly Jeep Wrangler JK shows starter problems more frequently than other models do.

Reason 2: Damaged Spark Plug

A faulty spark plug also causes the engine to not start. There are reasons like dirty spark plugs or dirty air filters that may cause faulty spark plugs. For detecting the spark plug problem here is the symptoms and solutions to the problem-

Symptoms:

The most common symptoms of faulty spark plugs are-

Rough idling
Vehicle won’t start
Engine hard to start
Poor fuel economy
Poor acceleration

Solution:

Usually the best way of solving spark plug problem is to replace the spark plugs. The steps are described in the following-

First of all, disconnect all the electric supply to the ignition
Secondly, remove the ignition coil
Thirdly, with the help of compressed air, get rid of all the dirt inside the spark plug tubes
Further, use a ratchet, unscrew the spark plugs
Furthermore, take the new spark plug and measure the electrode gap which should be according to the owners manual
Install the new spark plug and tighten with torque wrench
Finally, reinstall electric connections and coils according to the previous setup

Damaged spark plug problem is more prominent in Jeep Wrangler which eventually leads to the engine not starting due to overheating.

Reason 3: Fuel Injector Problem

Bad fuel injector is one of the most common problems with most vehicles. And this injector problem leads to engine overheating which causes the engine to not start.

So for a jeep owner, it’s very important to be aware of such problems along with the symptoms and solutions to this.

Symptoms:

Here are the symptoms that clearly indicate, your jeep is having an injector problem-

Loss of power
Improper idling
Engine not starting or difficult to start
Less mileage in fuel
Smell of fuel

Solution:

After you are sure of the issue, you need to take immediate steps to solve this problem. Sometimes it is recommended to replace the entire fuel injector. Which is pretty costly. So it is always best to clean the dirty fuel injector or clogged injector if you can detect it properly.

Here are the solutions to the fuel injector problem for your jeep:

If the injector is clogged, clean it
If it is dirty but not fully clogged, clean it with a good injector cleaner

Cleaning of Dirty or Clogged Fuel Injector:

For detecting whether your injector is dirty or clogged, you will be needing two things. The first one is the pressure gauge and fuel injector tester. The fuel injector is placed under the fuse box.

Here the fuel injector is used for supplying ground and voltage for the price amount of time in each injector. For testing, using a multimeter, measure the resistance of the injectors. If the reading of resistance is not close or equal then the one which is varying the most is the dead fuel injector.

For a dirty fuel injector cleaning-

Take the injectors and remove the two-o rings located at the end of the injectors
Take a marine heat shrink tubing. It has to be a heat-activated adhesive lining one
Take a good carb cleaner and flow the liquid through the injector
Use multiple shapes of hoses for getting a good amount of pressure
Use the bigger rubber hose on the injector and shrink the hoes size to the carb cleaner
Use a soldering iron for the rubber hoses to shrink them and fit properly
Get the fuel injector setup with the fuel injector tester
Adjust the setting for a different amount of carb cleaner passing and clean the injector carefully

When you are done with the process, reset the fuel injectors in the fuel rail and set it back to the vehicle for testing. For more details, you can check this video.

You will notice this issue mostly on Jeep Liberty, Grand Cherokee, and jeep wrangler due to fuel injection problems.

Reason 4: Battery Issue

Dead or dying battery is a well-known problem for people who are dealing with jeeps.

The warning light blinking problem can also occur if your battery is dysfunctional. Since the lights and radio are also operated by the battery, this can be a reason for system overheating, hence the engine won’t start issue may arise.

Symptoms:

These are the common symptoms for battery issues in the jeep-

Battery power is too low while starting the engine
Engine won’t crank
Dim or flaking headlights
Fluid leakage sign
Engine starts and dies immediately

Solution:

As soon as you identify the issue of battery, you need to start working on it right away. Otherwise, you might face problems like-trailer battery not charging, so here is the solution to the battery issue of the jeep-

Jump Start the Battery:

For dead batteries, sometimes jump start does the magic. Here is the process of jumpstarting your system-

Connect the red cable of the battery with the positive terminal
Connect the other end of the red cable to the donor battery
Connect the black terminal of the battery to the negative terminal of the donor battery
Connect the other end of the black cable to the engine
Start the jeep
Remove the cables in reverse order of application

Replace the Dead Battery:

If jump starting doesn’t help, this is how you can replace your battery-

At first, make sure you disconnect the negative terminal of the battery first
Then disconnect the positive terminal of the battery
Next, take off all the bolts for taking the battery out
After that, clean the disconnected terminals and underneath the battery
Next, place the new battery to the right place
Up next, screw in all the bolts and tighten properly
Now again connect the positive terminal first and then the negative ones
Finally, for better performance and to avoid corrosion, apply some grease on the terminals

Jeep Wrangler JK shows battery issue more often which causes engine overheating, hence it causes engine not starting problem.

Reason 5: Corroded Battery Cable

Other than dead batteries, corroded battery terminals are also a problem that causes overheating of the system.

Let’s see how can we detect this problem and how we can solve this problem in the easiest way possible.

Symptoms:

These are the symptoms that clearly indicate the corroded battery cables in your vehicle-

Engine fails to start
Engine cranks slow
Dim interior lighting
Electricity loss
Engine stalling

Solution:

It is always best to replace the corroded battery terminals if it doesn’t help while corrosion is removed. Here are the steps of it-

Pull off the wiring first that is attaching the batteries
Take a closure to look to detect the terminal type
Clean the battery terminals that are corroded already
Cut off the old terminal wires with new ones
Add heat shrink for better attachment in tubing
Connect all the shrunk wires appropriately

You will notice corroded battery terminal problem in Jeep XJ mostly.

Frequently Asked Questions (FAQs):

Why the jeep doesn’t start sometimes?

Alternator issues, dead batteries, or starter problems are the most common reasons why a jeep doesn’t start sometimes. Other than these issues, there might be a few more like ignition issues or fuel filter issues. But primarily, these three are the most common problems that may cause such issues.

Can lack of fuel cause the jeep won’t start a problem?

Yes, lack of fuel can cause the jeep not starting problem. If you have an issue with your engine, then low engine fuel is one of the indicators. If the fuel level is low, it won’t be able to provide enough lubrication. That may stop the critical components of the engine to function properly. Engine failure or jeep won’t start can arise for that reason.

Will lack of oil destroy the jeep?

If you are running your vehicle with a lack of oil, that may destroy some internal components of your vehicle. Engine oil is meant to provide better lubrication to the critical parts that move inside the engine. So lack of oil can create fiction among the parts. So it might not destroy your jeep but can hamper some critical parts.

Conclusion

Hope we could help you enough with all the details on Jeep won’t start when hot. Now you know what are the possible causes of the problem, the reasons, and the solution to those problems.

Before ending we want to leave a simple tip, that is not to start fixing your jeep problem without proper inspection. You must detect the root of the problem and ensure that you are on the right track. And finally, do not forget the regular maintenance of your vehicle.