Chrysler 3.6L Pentastar Overheating – Causes & Solutions

Since the 3.6L V6 first arrived on the scene in 2010, it has been used in over 10 million Jeep, Ram, and Dodge vehicles. The 3.6 Pentastar is known for its longevity and impressive factory performance. While the Pentastar V6 is unquestionably reliable, every engine is susceptible to faults every once in a while. For the most part, the Pentastar doesn’t have any critical design flaws that cause major headaches for Jeep, Ram, and Dodge owners.

With that being said, the 3.6L Pentastar’s cooling system is known to be subpar and can fail with short or no notice. That can lead to more significant issues, like overheating, down the line if left unchecked. In this guide, we’ll cover the most common problems with the FCA 3.6L Pentastar’s cooling system and discuss how those issues can be fixed.

3.6L Pentastar Overheating – Factory Cooling System Design

Before we jump into the primary causes and symptoms of 3.6L Pentastar overheating, let’s first talk a bit about the factory Pentastar cooling system design. It is widely known that FCA designed the Pentastar to operate at much higher temperatures than most engines. 

For instance, the 3.6 Pentastar’s thermostat doesn’t open until around 221 degrees. Additionally, the radiator fan doesn’t kick on to its highest setting until around 230 degrees. In most other engines, the thermostat will open around the 180-195 degrees Fahrenheit range. The high operating temperatures of these components don’t leave very much breathing room between normal operating temperature and overheating. This is one reason why overheating is common among FCA Pentastar-equipped Jeeps, Rams, and Dodges. That is especially true for abnormally hot days. 

Chrysler is aware of the high operating temperatures for the FCA Pentastar. They claim that this was an intentional design decision, but many enthusiasts say that that was a questionable decision. Others claim that the Chrysler engineers learned about the problem too late in the engine’s development and simply didn’t want to rectify the issue. Regardless, the high “normal operating temperature” of the 3.6L V6 is a major reason for 3.6L Pentastar overheating issues down the line.

Overheating Symptoms

Overall, it is pretty easy to identify an overheating 3.6L Pentastar V6. The most obvious indicator that your engine is overheating is the temperature gauge in your dash. As we covered in the previous section, the 3.6L Pentastar was designed to run at a higher operating temperature than most other engines. As a result, it isn’t uncommon to see the temp gauge needle extending to nearly the ¾ mark. It isn’t until the needle reaches the highlighted red area that you know that the engine has exceeded its normal operating temperature.

Sometimes, a 3.6L Pentastar overheating event will cause steam to come from under the hood. This is an indicator that the expansion tank might have cracked. Depending on what coolant system component has failed, the engine will also likely be leaking fluid onto the ground. It is important to take note of where the coolant is leaking from so that you can identify the component that you’ll need to replace. A leak towards the front of the engine can indicate a radiator leak or damage or a water pump leak.

If a 3.6L Pentastar overheats, it will trigger an engine fault code. A P0217 engine code is a giveaway that the engine has reached a high internal temperature due to a failed cooling system component. There will likely be other accompanying codes as well.

Ultimately, if you notice any of these symptoms, especially if you notice that your vehicle’s temp gauge needle is in the highlighted red section, stop the vehicle as soon as you can safely. The longer you drive with an overheating Pentastar V6 the more damage is likely to be done. 

3.6L Pentastar Overheating Causes

Generally speaking, when a factory engine overheats, there is typically something wrong with the engine’s cooling system. That isn’t surprising, as high internal temperatures are exactly what an engine’s cooling system is designed to combat.

The 3.6L Pentastar, as well as nearly every internal combustion engine under the sun, uses a circuit of coolant pipes, a thermostat, a radiator, a water pump, and multiple sensors to pump coolant throughout the engine, drawing heat away from hot internal components. If there is an issue with any of these cooling system components, parts of the 3.6L Pentastar can get hotter than they are meant to, potentially causing severe damage. 

Unfortunately, the 3.6L Pentastar V6 is known to have multiple weaknesses within its cooling system. Some of the issues arise due to the way in which Chrysler casts their engines. Other issues stem from parts degrading over time, perhaps more rapidly than with other engines. Overall, the main causes for a 3.6L Pentastar overheating are as follows:

• Water Pump / Thermostat Failure
• Clogged or Damaged FCA Pentastar Radiator
• Inadequate Airflow to the Radiator

Water Pump/Thermostat Failure

One of the most common reasons that a 3.6L Pentastar overheats is a failing water pump or thermostat. Both components play a critical role in keeping the FCA V6 in its normal temperature range. 

As the engine runs, the water pump continuously circulates coolant, drawing it from the radiator and pushing it through the engine block and cylinder head. This process helps to dissipate heat from the engine and keep it operating at a safe temperature. While the Pentastar water pump circulates the coolant, the thermostat is a temperature-sensitive valve that regulates the flow of coolant through the engine. It is typically located between the engine and the radiator, and it opens and closes as needed to maintain the engine’s temperature within a certain range. 

If the Pentastar V6’s water pump fails or is leaking profusely, not enough coolant gets circulated through the engine. This means that heat isn’t drawn away from the engine, causing it to overheat. Thermostats fail a bit differently. Sometimes a failing thermostat will fail to open at the desired coolant temperature, preventing coolant from continuing through the system. This will cause your 3.6L Pentastar to overheat. Inversely, thermostats can get stuck open which will prevent the engine from reaching normal operating temperature quickly.

While these are wear and tear parts, the Pentastar’s abnormally high operating temps can cause these parts to wear faster than normal. 

Failing Water Pump/Thermostat Fix

Water Pump Price: $173.00

Thermostat Price: $39.92

When it comes to replacing or repairing broken cooling system components, it is a good idea to have them professionally replaced if you aren’t familiar with automotive maintenance. The main reason is that the cooling system is pressurized and needs to be bled after a major service which can be difficult for beginners. As we’ve already covered, the cooling system is vital in the proper operation of the engine. In general, it’s better to have a trained technician replace the Pentastar water pump or thermostat than to risk further complications later.

With that being said, it is possible to replace both components without any specialty tools if you are comfortable performing a DIY job. If you are interested in doing the job yourself, check out this video that does a good job of walking you through the process:

As far as overall costs are concerned, 3.6L Pentastar cooling system repairs can be somewhat costly if you take your vehicle to a certified FCA repair facility. If it is determined that you need your 3.6 Pentastar water pump replaced, a dealer would likely charge around $500 for parts and labor. The 3.6L V6 water pump itself runs around $170, so that is the approximate cost of a DIY repair. Replacing a Pentastar thermostat is a bit less expensive, averaging around $400 for a dealer install. The thermostat itself only costs around $50. The installation is a bit more involved than the water pump, though.

3.6L Pentastar Overheating – Clogged or Damaged Radiator

Aside from the water pump and thermostat, the radiator is the most critical component of the 3.6L Pentastar’s cooling system. The job of the radiator is to transfer the heat from the engine coolant to the surrounding air. It does this by using a series of thin tubes and fins, which increase the surface area of the radiator and provide more opportunities for the heat to escape.

There is a unique problem that 3.6L Pentastar engines face as far as their radiator is concerned. The issue stems from the sand casting process that FCA uses to manufacture its engines. The aluminum heads found on the 3.6L FCA Pentastar are made by pouring aluminum into a sand mold. While this works well and very little residual sand is left behind, some leftover sand can stay in the components and enter the cooling system later down the line. This can cause sludge and deposits throughout the cooling system. 

Other debris can enter the cooling system through the radiator and other areas of the cooling system. This debris can get caught in the radiator itself and stop coolant from flowing through it. This causes major issues for the rest of the cooling system which relies on the radiator to supply cool coolant. 

The radiator is one of the most forward-facing components in the 3.6L V6 engine bay. As such, it is common for road debris to damage the structure of the radiator itself. Radiators can also be damaged in collisions or if it scrapes on a piece of high terrain. These holes can cause coolant to leak, leading to potential 3.6L Pentastar overheating issues.

Clogged or Damaged Radiator Fix

3.6L Pentastar Radiator Cost: $90.00

Unlike with the water pump and thermostat, you don’t necessarily have to purchase an entirely new radiator if the one in your engine is clogged. It is possible to remove the radiator and remove the debris that has collected in it. There are numerous ways to clean a radiator, but we’ll link a video that shows the process in detail below. 

With that being said, the story is different if your 3.6L FCA V6 radiator is damaged. If there are significant holes caused by debris, they can cause the radiator to lose overall effectiveness. Chances are there will be coolant leaks if there is damage to the bottom of the radiator. If either of these is the case, chances are that you’ll need to replace the radiator entirely. Left to a dealership, the replacement could cost upwards of $1,000 including parts and labor. If done DIY, the cost would probably be closer to $200-$250.

Inadequate Airflow to the Radiator

In line with the radiator issues that we have already covered, one often unforeseen cause of 3.6L Pentastar overheating is a lack of airflow to the radiator due to aftermarket additions. The 3.6L Pentastar is used in a number of off-road capable vehicles like the Jeep Wrangler and Ram 1500. As a result, frontal modifications like large winches, lightbars, and trail lights are often mounted on these vehicles. 

Some of these add-ons are so large that they block off a large portion of the front air inlets which allows air to reach the radiator. If air can’t travel effectively through the front of the vehicle, the cooling system might fail to work correctly. This is a common occurrence, with many Chrysler 3.6L vehicles talking about it on the forums.

One common fix is to install a breathable aftermarket hood, which gives air another route into the engine bay. Some of the most common brands include AEV, MV8, and Crawler Concept. Some Chrysler V6 owners also opt to remove their inner fender lining which also allows more air into the engine compartment.