NEW JEEP - BREAK-IN / OIL CHANGES

[TheTanSedan]

My wife has an '01 Cherokee with the 242 straight six. Changed to M1 10w-30 at 3000, then to M1 0W-40 after a 1k treatment with Auto-Rx at 36k.

Changes are at about 6k, with M1-301 filter. Vehicle sees an average 500 miles/week in business driving (mostly freeway), consumption is zero. Never any piston slap (wasn't even aware it was an issue with these motors until reading on another board).

Auto-Rx removed an incipient varnishing/glaze as observed in oil cap; used mainly for peace of mind. All other service is well-ahead of schedule.

This vehicle is driven conservatively (looks like OEM brakes and tires will both exceed 75k before replacement mandatory), but also runs in extremely hot Dallas weather.

Mobil One 0W-40 was chosen for any slight advantage it would have in hot running conditions.

 

[JonC]

TanSedan,
Did you notice any difference in running the 0W40 vs the 10W30? Have you done any UOA? I've been running M1 10W30 for 70K in my '99 4.0L engine, but have recently entertained the idea of trying out the 0W40.

Jon

 

[TheTanSedan]

No UOA yet, am waiting to change to a second fill of M1 0w-40 before a 2100-mile roundtrip in early May, and expect the next change in mid-late July. That will be a period consistent with the hardest running for the car as daytime temps will be exceeding 100F, nights at or near 90F, and constant A/C use during operation in a period of summer with the highest ambient humidity. This vehicle has such poor underhood airflow management that it takes -- literally -- a pair of leather gloves to open the hood.

That is the point a sample will be drawn and the Blackstone/Dyson analysis done.

0W-40 will have its mettle tested for this vehicle during this period.

This is also why I have -- on the OIL FILTERS forum -- posted questions in regards BALDWIN and DONALDSON filters for this car to try (as Terry Dyson has indicated a preference for) an easy flowing fiberglass media filter.