started using full synthetic at my last change (52,000). I used mobile 1, but it seems quite a bit more expensive than castrol. is it really worth it?

Yes, and i wouldn't switch back if you've already gone synthetic -- may be an old myth, but I've heard it's no bueno for seals/valves/rings to go backward

won't switch back, but castrol has full synthetic too.

Yes:

1) If you are doing 20,000 mile oil changes.
2) Your going to keep the vehicle for 10+ years

I believe that it is just a myth. Any synthetic blend or full synthetic is going to get you the benefits that you are looking for. I use Motorcraft synthetic blend, and it is hardly any more expensive than straight penzoil dinosaur oil.

Not sure what they put in mine.

Walmart caries their own brand of oil supertech. They also cary a synthetic variety of it. Ive been running it in my wifes car for over 120,000 miles and its great. Oil analysis is great as well.

If they made the oil my truck calls for i would use it in a heart beat.

Absolutely 0 chance any of my vehicles get oil changed at the Walmarts

first time I've ever had mine changed will be this weekend.

You can buy walmart branded oil without letting them change your oil.

I dont change it at walmart, just buy the oil there off the shelf. Its about the cheapest oil you will find. They carry a bunch of it too.

Mobil one is all I used on my 17' new 2021 f-150 is gonna be a diesel and I'll use Rotella.

You and Texas Dan. Lol it up.

I always buy my oil at Walmart but change it myself. Been doing it since I was a teenager. It gives me the chance to see what's going on underneath and detect anything that might need attention. I also split hairs and have always used Valvoline's Synthetic Blend Oil in both the car and truck.

x2 - been using SuperTech Full-syn 5w30 (& fram-Ultra Synth filter) every 7.5k mi for last 260,000 miles changed myself on Chevy Vortec 6.0L
(total = 360,000 miles now; first 100k miles was plain penzoil and fram filter every 3k miles @ Walmart garage, but that was before 2007 - wouldn't do now...)
Hardly have to top-off between changes (-0- for first 300k miles, about a half-quart these days - rear main seal mostly).

I don’t trust those jack wagons working on my stuff. If I’m not doing it, it’s the dealership. It’s the vanity in my I reckon

I no longer drive enough to study about it.

Bought my last two sets of tires at walmart. I was skeptical and surprised a cute petite polite little lady took care of them both time. She doesnt look the part at all but i have zero complaints. I dont buy monster truck wanna be tires, so walmart is pretty darn hard to beat on tires. I have no pride about where i buy my tires from so im happy to buy them there.

FWIW, most of the high end cars call for Mobile 1 synthetic....I assume they do that for a reason. That's all I've used in my vehicles for years.

wouldn't say mines high end, but I want it to last. I'll stick with the mobile 1. went 8000 on this change. 85% highway miles.

You likely won’t smell it like I do, but I have always ran Rotella T5 synthetic blend until this this last oil change when I switched to Rotella T6 full synthetic. The T6 is absolutely nauseating with my truck being deleted and sitting idle.

I wonder why the oil smells so bad?

I know mine is a different animal as it an ecodiesel and not a cummins, but the T6 doesnt smell at all in mine. Stock or tuned.

Dad's '18 cummins is stock, but run the regular old white jug rotella in it and no weird smells.

15 f150 ecoboost Motorcraft blend every 5000 to 6000 miles. Just rolled over 60000 miles.
03 Dodge 4.7 straight Valvoline . Every 5000 miles. Fixing to turn over 179000.

Smart man for doing the oil analysis. That's the ONLY way you know how your oil is performing. The Walmart synthetic and Costco (Kirkland) synthetic are both made by the same company.

I'm running Amsoil in my 2020 Ram Ecodiesel.