Hello, as the title suggests above I purchased a 1994 Ford F-150. 4.9L in-line 6 300. 91,000 miles, 2WD. I have had it for a little bit now, and it's time for an oil change. My manual says to put 5w30 oil in it, but there was a manufacturing update a few years ago now calling for 5w20 oil in those motors. I am a little worried about putting thinner oil in this old truck, which oil should I put in it? As far as climate goes, I live in central Illinois. It's hot as shit in the summer, and cold as hell in the winter. Any response would be greatly appreciated, thank you!
I would stick to the 5w30. They did that with my old ranger too even though there is a sticker under the hood saying to use 5w30. I am using 5w30 and I live in Missouri so pretty much same weather. I am not sure why they suddenly switched. Probably to satisfy those "CAFE" standards or whatever.
@alban123
I'm sure part of it is for the CAFE standards. One of my good friends is a mechanic, and is actually certified to work on Fords. He says the reason they made the change was because of performance issues? He didn't go into much detail, but told me to get another professional opinion if I was worried about it.