I've heard of many people say 0wXX can be ran year round and with good results, but I guess it just seems strange to run a 0w in an engine that originally came with a 5w or 10w recommendation in the manual. But, as was stated, there is a lot of misinformation when oil is discussed. I don't want to add to any of it, and I am BY NO MEANS an oil pro. I'll just say I use the Rotella T6 5w40 and like it. I know 0wXX is probably better and I don't completely understand the physics of oil, but I (to an extent) enjoy being uneducated in the matter and will stick with what seems to be working for me.

 

I've been running 5w/30 M1 in mine for a couple of years now. I use the larger M1-301 filter.

 

you can switch back and forth it doesnt matter. Going to a GOOD synthetic is a great idea. However Mobil one would not qualify as that.
Look into amsoil. I believe a lot of the Napa franchises now carry it also.

 

Theoretically, you could potentially see a little higher oil pressure when switching to a higher viscosity oil...anyone seen this?

 

I understand that a thicker oil would have higher pressures. My oil pressures are less than what I would like. I never get over 30 psi running hot. I replaced the sending unit too. The oil pump may be a bit weak. I am the original poster on this thread.

The irony is that perhaps a thinner oil would get better flow through the engine even though the pressure would likely be lower. So, is it flow versus pressure, or a combination?

Anyway, it seems like synthetic is the way to go with a 5w30 or a 0w40 and either can cover all seasons....at least that's what I'm reading into this.

Thanks for all of your feedback.

 

10w-30 in finne for the winter depending on how cold it gets there. If your average temps are from 10 - 32 deg F. 5w-30 wouls be better.

 

Winter and "above 32" does not compute....

 

When I worked at the jeep dealer last year changing oil, we were taught the problem with going to conventional to synthetic is that the molecules are smaller in synthetic, and that on older vehicles it can cause a lot of motor oil leaks because its easier for the synthetic to fit through crevices with the smaller molecules.

 

X2^^^

 

Wrong again...
Modern synthetic has seal conditioners and stuff to keep that from happening.

 

So does regular dino oil...

 

It's almost double the price of other synth oils. Does it last twice as long? Provide twice the protection?

 

Lifetime warranty...?

 

That's another old wive's tale that refuses to die.

The big issue with our Jeeps is the oil filters. Since our Jeeps have the oil filters mounted upside-down or sideways, it is imperative that the oil filters we use have an excellent anti-drainback valve. Without that, we start our engines lubricating with air because all of the oil drained oil while parked. Not good. Wix, Napa Gold are good and easy to find. There are other good oil filters out there, too. One in particular to avoid is Fram- the OCOD. Orange Cans Of Death.

http://minimopar.knizefamily.net/oil.../opinions.html


By the way, It's Mobil not mobile.

 

Yeah well its happened to me twice on higher mileage cars, and once on an '02 Ford...so I'm an old wife?