The 3.6 Pentastar Engine has a number of variations fitted to a variety of Jeep and other Stellantis products. This platform is used in the WK2 Jeep Grand Cherokee, JK Wranglers, JL Wranglers JT Gladiators and we have even seen them in a few Chrysler voyagers and dodge products too. Equally so, the KL Cherokee runs a 3.2 v6 which is very similar and prone to the same failures.
All of these engine platforms regardless of the age or series are susceptible to this unique issue that we have only seen on the Pentastar engine before.
The issue is starter motor failure. Unfortunately once a starter motor has failed you need to replace it before you can go any further with your diagnostics you are going to have to start with a replacement starter, however this may not be the end of the issue for that particular car.
Chances are if your reading this it is because you, as the owner have had several starters go down or you’re a mechanic researching why you have a Jeep product that keeps killing starter motors. its not a faulty starter.
The issue is the cooling system. The combustion chambers or one of them is hydrolic locking and the starter motor is burning out by trying to start a car with coolant in the combustion chambers.
There are two cuases for this, blown head gaskets and EGR coolers.
If you are replacing starter motors frequently in a jeep product. Check your cooling system.
Here is a short video talking you through this fault.
