2024-2025 Jeep Compass Engine Oil Dilution Issue

Owners of 2024-2025 Jeep Compass and 2024 Jeep Renegade Mild Hybrid Electric Vehicles (MHEV) may notice their Internal Combustion Engine (ICE) operating more frequently than expected, even when electric propulsion should be active. This behavior is linked to a condition known as engine oil dilution, as described in Stellantis STAR Online Publication S2418000015, released in November 2024.

The document explains that this Jeep Compass engine oil dilution issue is a known phenomenon in MHEV vehicles, particularly under certain driving conditions. Understanding this process can help owners manage their vehicle's performance and longevity.

Understanding Engine Oil Dilution

Engine oil dilution occurs when gasoline (petrol) mixes with the engine oil in the oil pan. In MHEV vehicles, this is more common because the ICE frequently starts and stops, especially during short trips or in cold weather. When the engine is cold, fuel may not fully vaporize and can condense on cylinder walls, eventually making its way into the oil pan.

This phenomenon is particularly prevalent when the vehicle is driven for only a few kilometers at a time, especially in low ambient temperatures. The short drive cycles do not allow the engine to reach its optimal operating temperature of approximately 80°C (176°F) or higher. At these lower temperatures, gasoline cannot effectively evaporate from the crankcase and re-enter the ICE for combustion, leading to an increase in oil dilution.

Symptoms You Might Notice

The primary symptom of Jeep Compass engine oil dilution is the "Unexpected Operation of the ICE (Internal Combustion Engine) Instead of Electric Operation." This means your vehicle's gasoline engine may run more often than you anticipate, even when the system would typically use electric power.

As the control system detects increasing oil dilution, it will actively try to keep the ICE running to help evaporate the fuel from the oil. Drivers may first notice the unavailability of the Stop & Start function. Following this, the electric propulsion system may also become unavailable. In severe cases, you might receive a dashboard message requesting an oil change, indicating that the oil dilution has reached a point where the vehicle's internal strategy can no longer correct it.

How the Vehicle Manages Oil Dilution

To counteract engine oil dilution, the vehicle's control system employs a strategy to inhibit the operation of the electric motor. This allows the ICE to run continuously, bringing the engine oil up to temperature. Once the oil reaches approximately 80°C, the gasoline mixed in the oil can evaporate from the crankcase and be re-combusted by the engine, effectively reducing the dilution.

The electric motor will resume normal operation once the engine oil regeneration process has successfully reduced the dilution to optimal levels. This strategy is designed to maintain engine health and performance.

Recommended Owner Action

To help prevent or mitigate Jeep Compass engine oil dilution, especially in low-temperature conditions, it is recommended to periodically drive your vehicle with the ICE engine running for a sustained period. Specifically, Stellantis advises driving for 60 consecutive minutes once a month.

This can be achieved by driving in extra-urban areas, where sustained engine operation is more feasible. You can also activate the eAuto Off function or select D mode, depending on your vehicle, to encourage the ICE to run continuously. This practice helps the engine reach and maintain the temperature needed to evaporate fuel from the oil, thereby reducing dilution.

Important Information for Owners

It is important to note that Stellantis STAR Online Publication S2418000015 is an informational document. It states: "This document does not authorize warranty repairs. This communication documents a record of past experiences. STAR Online does not provide any conclusions about what is wrong with the vehicle. Rather, it captures all previous cases known that appear to be similar or related to the vehicle symptom / condition. You are the expert, and you are responsible for deciding on the appropriate course of action."

This means that while the document explains the phenomenon and offers advice, it does not automatically qualify for warranty repairs based solely on the communication. Owners experiencing persistent issues should consult their dealership for diagnosis and potential solutions.

Source: NHTSA ID 11010503