00xjsport89

I recently purchased a 2000 xj sport 4.0 with 157kilometers on it from out west (yellowknife). Its in excellent shape and id like to keep it that way. When i got it, i noticed on the maintenance receipts, that it was on full synthetic 10w30. So i went to my usual brand of mobil one synthetic when i changed the oil. Worked fine, i noticed a little valve train noise but i guess thats usual for a 4.0?? Anyways for the next change all they had was rotella t triple protection 10w30 and i always read how alot of you guys like rotella products so i thought id give it a try. Right away i noticed the engine was quieter and the oil pressure was bumped up about 10 psi. I thought great! But i guess what i wanna know is rotella diesel oil really better for a jeep? And if so what exact type and weight should i be running? Like i said it has 157k but is really strong. Any thoughts would be appreiciated!

RTorrez1

That is all I will run in my XJ. But I run Rotella 15w40 and I have never had a single problem with it. One of the main reasons so many like the Rotella oil is because of the higher zink which the 4.0 needs. BTW, Make sure that you run a good quality filter and stay away from the Fram crap! Many on here including myself recommend Mopar, Wix or the Napa Gold brands.

rzldzl

i run the cheapest 5w30 dino oil year round.

change it once a year, in May, regardless of miles.

run the cheapest filter too, most of the time, fram

salad

Yes, many of the heavy duty diesel oils on the market work very very well in XJs. A lot of people don't realize that the majority are API certified for use in gasoline engines as well. Feel free to run a 40-weight multigrade, just beware that your fuel economy will tank and you need to let it warm up a bit more. Plenty of us here run 0w40 through 15w40. If you want to get really nerdy, look on http://www.bobistheoilguy.com/ for used oil analyses for the Jeep 4.0L.

While the topic of oils in the 4.0L is vast, as long as you stay within the correct viscosity range the significance pales in comparison to the effect of running a ****ty filter. Stay the hell away from FRAM, STP, Quaker State, and other similarly price units. WIX manufactures filters under it's own brand, as well as providing *SAME SPEC* units to NAPA for their Gold series and CarQuest for their Blue series. Purolator is also a great filter in a reasonable price range; aside from direct sales they provide *SAME SPEC* OEM units to Motorcraft and probably a couple others.

http://www.minimopar.net/oilfilters/reference.html

00xjsport89

Thanks guys but as always your responces leave me confused... so i shouldnt go with 10w30? I should use 5w40? I just really want the best protection possible, i always use napa gold filters so no worries there but i live in nova scotia so it gets cold up here so maybe 5w40 is to thick?

xjsnake

Nova Scotia? 10-30 is probably the heaviest I'd run up there.

salad

Oh in NS? Run something that flows better on startup. 0w30 to 5w30 or 0w40 to 5w40. Crappy Tire and PartSource carry Rotella T5 and T6 in those weights and they go on sale every so often.

00xjsport89

Yes NS lol, so ifbi want the best t6 in a 5w40 would be best?

salad

Sure. It's the only grade of the T6 line I've seen around here.

Now all that aside, while 4.0Ls perform very very well on 5w40s (AMSOIL, Mobil Delvac, and Shell Rotella), they're all synthetics. If your rings are bad and your engine dumps a lot of fuel into the oil don't expect any extended oil change intervals.

00xjsport89

Doesnt burn or leak a single drop, thanks ill give it a try

salad

It might not - check your old oil for gasoline. It's one of the reason that frequent in-city trips demands a higher oil change interval: the oil gets diluted with fuel. Ain't no filtering that out.

kgm

You see mileage drop running a 40w? I was thinking about going to 5w40 for my next change and seeing how it does. I like my high teens mileage though.

salad

Yes, slightly.

bigbadon

At operating temperature the difference is hardly measurable.
The 5 wt will save a little when cold the 2nd number regardless if it is 30 or 40 means little as far as mileage goes.

belvedere

I would run any quality 5W30.