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Rotella 15w40 vs Rotella 15w40 Full Synthetic
You Should Use ONLY Ford motor craft 15w 40 in the summer and 10w 40 in the winter. Just my Opinion. You can use 15w 40 in the winter too but 10w helps with cold starts and runs smoother.- Jason578434
- Post #33
- Forum: 6.9L IH & 7.3L IDI Diesels
