Owner reviews for engine oil

I use rotella 15w-40, high zinc content but my engine also has 230k miles

I've been using Mobil 1 10w30 regular and now High-Mileage Synthetic for decades and most of the Jeeps life.

5-30 Valvoline restore & protect is working wonders on my 2.5. Visibly cleaning out deposits and engine running stronger

There’s been a lot of advancements in oils since the YJ was new. I use Mobil 1 0w40 in mine due to its excellent temperature range and proven endurance.

I use one oil - shell rotella. It goes in my XRL my 4.0 Jeep and my 7.3IDI diesel ????

I use Castrol Magnatec A3/B4 10W-40 part synthetic. 3 years now and no problems.

Mobile 1 full synthetic 0W-20 every 5K. My engine hums like a top.

I always used gn4 but switched to rotella t6 15w40 cheaper, full synthetic. it can handle the heat alittle better and I like the shift quality over gn4. Walmart has it for cheap

My changes have generally been religious at 5k and that didn’t save my GTI from losing compression in cyl3 at 37k untuned miles it suffered 15% leakdown vs the other 3. That car got M1 0w-40, tried and true stuff, so you just never know.

I switched to Rotella T6 (5w-40 Full Synth) after running Penzoil, Chevron, Castrol, Mobil, regular non-high mileage 10w-30 dinos in that order over 4000 miles. Worst of this bunch was Mobil and Chevron, the HLA tick was unbearable, even right after the oil change.