jonc

From the book, "The Lifetime Powertrain Limited Warranty covers the cost of all parts and labor needed to repair a powertrain component listed in section E below that is defective in workmanship and materials."
Normal wear is not covered,

mdantonio

Hi! I switched to Mobil 1 EP at 3000 miles. In the winter season I change it every 3000 miles (reasoning extreme temperature changes "may" instill some condensation) and every 6000 during the "better" seasons. I start the vehicle, drive 50 miles to work and repeat after work. The Jeep definately gets thoughly warmed up and there is no "stop and go" or "continuous high speed" driving. I DO however have the dealership install the MOPAR oil filter. (I have all of the maintainence work performed at the dealership so I at least will have some "ammunition" if the worst happens!) Take care... Mike

bobzinger

I'm about to roll 37K. Would it still be ok to switch? What is the benefit of switching to synthetic?

mjcrna

Credability obviously isn't established by just saying this but, my neighbor is actually a petrol scientist, who works for Caterpillar (CAT). He basically recommends, (9 out of 10 petrol scientist do, ), only using synthetic if you still intend to change every 3-5k miles, and you are using your vehicle at the limits of its operating range (us jeepers who actually offroad). He agrees with the premise that the synthetic has broader temperature stabilities, low boil off, low oxidation, so better lube at extremes of temperatures. SO they synthetics as you'd expect, hold up longer, the base at least. The problem is that though the synthetic base lasts longer, both conventional and synth additives wear out at the same rate. Additives are things like detergents (sludge prevention), molybdenum (friction modifier, mpg), antifoams, antioxidants, seal conditioners, etc. SO use it if you do more than pavement drive, but don't waste your money for a grocery getter. Just change the oil at recommended intervals, don't try to go 10-15k cuz it's synthetic, the base is the only thing that lasts longer, and oil does more than lube metal to metal.

BTW, this has been a change of practice for me. I'd always used synthetic in all my cars; now I just save my money, except for the jeep. It gets mobil 1 every 3-5k

mjcrna

oh going to it early is of course fine. It really makes no difference, modern synthetics are completely compatible with conventional oils. Something to do with the esters in the early synthetics being incompatible that created the don't switch back and forth or go to early issues. Thats no longer true, but considering the consequences, you can check compatibility between oils on their websites.

Jiblet

Thanks, mjcrna, I agree completely; I mostly drive pavement but spend a lot of time in the mountains and do a little wheeling. I use Mobil-1 every 5-6,000 miles or 6-months.

I posted a question about synthetics (5w-20 vs. 5w-30) but nobody answered.

https://www.jk-forum.com/forums/jk-talk-26/synth-5w-20-verses-synth-5w-30-a-89094/

Any chance you could check it out and ask your neighbor? TIA

mjcrna

this is actually something I know already. As you can imagine I talk to my neighbor a lot. Basics: the first number is SAE base, and the second number is viscosity at operating temperature. SO 5 to start and 20 at running temp. The lower the first number the better (always, but read on). Viscosity modifiers (polymers etc) are used to get it up to 20 from whatever the starting point is (5 in your example), unfortunately these modifiers make the oil less thermally stable. Although raising the final viscosity from 20 to 30 would be good if operating in high temperatures or high mileage engines in theory, the Sahara desert or above 120,000 miles (arbitrary number I picked), it requires more modifiers to go from 5 to 30. Here is where this thread actually ties in keeping us on topic . . .. viscosity modifiers are less thermally stable, thus breaking down at high temps where you chose the high visc for in the first place. conventional oils are less stable at the temperature extremes, thus more breakdown, which is where again synthetics come in. SO if you stretch the multi visc oils out of whatever your vehicle specs for operating conditions rationales (above), from 20 to 30 for instance, make sure you use synthetic. otherwise you did yourself no good.

Edit: lol I just assumed your question, but didn't see the link your posted. I've subsquently read it, and see you know your stuff probably better than me, but I think I still kinda answered anyway, though way to simple terms for your question, but this is for all to learn from right! ? Basically, I think your right to go with 30 as long as you go synthetic, secondary to the spread in the multivisc ratio. We know the 30 is acceptable for the engine, the only question is what ratio to choose, and that doesn't matter as long as you go synthetic here.

geoffcwilson

How about time versus mileage? I've never followed that "or 3 months, whichever comes first" adage. If Jeep is not DD it could be sitting there a long time.....

Gr8ful

I am new here but I wanted to add my $0.02 worth. My C5 Corvette came from the factory filled with Mobil 1. I am going with it at 1k in the JK.

Muffins

Anyone see the commercials for Valvoline Synthetic? I wonder if it is any good? You can register your vehicle online (if under 75K) for a 300k warranty. That seems like a pretty bold offer and I'm sure there is fine print. Is Valvoline systhetic any good?

Also, I know a lot of people use mobil 1, but I've heard the base components of the oil, I'm not sure of the exact terminology, are not as good as Amsoil, Royal purple and brands like that. Is there any truth to this? How does Valvoline stack up? I've used their conventional oil for a long time and never had an issue but now that I'm switching to synthetic, I might stick with them. Aren't they all pretty much the same except for the additives? Sorry for the long post, thanks for the help.