TSB: Jeep Block Porosity

This bulletin applies to 2021-2024 Jeep Wrangler, Compass and Grand Cherokee vehicles equipped with a 2.0L I4 DOHC Turbo engine.

The vehicle may experience rough idle when cold starting and low coolant level in the recovery bottle. This may be due to cylinder block porosity.

Check for cracks and cooling system leakage. 

1. Cold start the engine to verify rough idle. The engine may run normally after 30 seconds.
2. Does the engine run rough on cold start then normal after 30 seconds? If yes, proceed to Step 3. If no, normal diagnosis is needed.
3. Identify the cylinder(s) having a misfire condition.
4. Set the cylinder(s) position to bottom dead center.
5. Using a cooling system pressure tester, pressurize the cooling system up to 21 psi with the engine at normal operating temperature for 12 minutes.
6. Observe for pressure decay on the tester gauge.
7. Using a borescope, inspect for any trace of coolant in the affected cylinder(s) while the system is still under pressure. Make sure to inspect the entire perimeter of the bore.
8. If coolant is detected in the affected cylinder(s), replace the engine long block assembly.