I was having some difficulty deciphering the oil specs on Pennzoil's pages so I did a little digging. There must be some formula differences between the Ultra and the Ultra Euro. Even though there own tech sheets contradicts that fact. The Ultra 0W-40 Full Synth Technical Data Sheet states:
PENNZOIL ULTRA™ FULL SYNTHETIC MOTOR OIL with Hyper Cleansing Technology™ is compatible with all
engine sealing materials, other synthetic oils and all conventional oils and is suitable for all cars, SUV’s, light vans and
trucks, gasoline and turbocharged engines, under all driving conditions where an API SN, SAE 0W-40 oil may be
recommended. Not for use in Porsche, Mercedes-Benz, BMW and other European engines.
Pennzoil Ultra TM is specifically formulated for the needs of Chrysler SRT engines where Chrysler MS-12633 oil is
required. It may also be used in SRT engines originally recommending Chrysler MS-10725 oil.
GPCDOC_X_cbe_24855_key_140007304050_201207271338.pdf
Yet Pennzoil shows that the Chrysler MS-10725 spec is compatible with MB 229.5 spec.
Pennzoil Ultra Full Synthetic Motor Oil - Pennzoil
From what I understand, Chrysler dealers now use the Ultra Euro 5W-40 exclusively for the Xfires.
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