Originally Posted By: Kuato
Been reading several threads where engines spec'd for xxW30 were being run with xxW40 with good results, usually the Jeep 4.0 inline six.
Wondering if anyone has experimented with a 40 weight oil in the Jeep 2.4L four banger? Same engine was found in Plymouth Breeze/Dodge Stratus/Chrysler Cirrus.
Thanks all for the input.
First off... what model Jeep are we talking here??? When Jeep became part of Chrysler, they kept the Jeep 2.5L pushrod 4 (related to the 4.0L six) and ditched the Chrysler-designed SOHC 2.5L that was being used in the Dakota. They kept the SOHC 2.5 in the Cloud cars until it was replaced by the Chrysler DOHC 2.4L, which was later used in the PT Cruiser, but I don't *think* was ever put in a Jeep of any sort (not 100% sure on that).
That said...
I've got a fill of M1 0w40 in Wifey's PT Cruiser right now. Butt dyno and ear-o-scopes don't show much difference between that and the M1 0w30 AFE that I ran prior, but then they shouldn't, really (and I don't put any confidence in people saying an engine "feels" or "sounds" better on one oil vs. another). I'll let you know in 6 months or so when we rack up enough time for a UOA, but I really don't expect much difference, it did fantastic on the 0w30AFE.
FWIW, I wouldn't consider running a 5w40 HDEO in this engine like I do in the Jeep 4.0, it just shouldn't need it. The M1 0w40 is a thinnish 40 wt whereas HDEO 5w40s are more near the mean thickness of 40 weights.
Now....
If you're talking about the JEEP designed PUSHROD 2.5L engine, then it should love a 5w40 HDEO just as much as the 4.0 does- its the same architecture just with 2 fewer cylinders and a shorter stroke.