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Old 05-22-2013, 03:45 PM   #1
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Oil Type for 4.0 Liter

I have always used regular 10W30 for my Jeep but now that is has almost 150,000 miles I was wandering if I should use a higher weight or even Synthetic. It has started using about 1 quart every 5,000 miles. What do you think?
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Old 05-22-2013, 03:52 PM   #2
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Everyone will tell you a thousand different things. Asking what brand of oil or asking what type of lift to install will get all sorts of folks barkin' about whats best for ya.

I won't tell you whats best. But I'll tell you what I run in my 94' 4.0 w/about 180,000 on it. I run Quaker State or Castrol GTX 5w-20. The 5-20 is a thinner oil and seems to lubricate to the top end much faster and keep my lifter ticking a lot quieter. I started going to thinner oil after realizing that anytime I put in a 10-40 or Lucas that my lifters ticked almost twice as loud as they do once the oil is thinned out.

Been runnin' 5w-20 year around w/no issues, no burning oil, no over heating and very minimul ticking from the top end. I'd say from experience, go thinner not thicker. But no matter what, figure out whats best for your engine. If you try a new oil, pay attention to the sound of it at idle at up through the gears once changed. Then, run it a couple weeks and see how it sounds. If you don't like it, change it to something else and re-compare how it runs. Should stay quiet and cool, thats what we want.

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Old 05-22-2013, 03:56 PM   #3

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I would look at Lucas oil stabilizer it's thick and sticky. It sticks to the metal which benefits you especially when the vehicle has sat a long time And all the oil is in the bottom of the Oil pan. I add a quart with every oil change to my jeep.

I used it on my Pathfinder got 275,000 miles... I saw the guy i sold it too...he's got over 300,000 and its still going!
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Old 05-22-2013, 05:59 PM   #4
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Anything will work in a 4.0l.. The tolerances on these oldschool motors are so loose it doesn't really matter. Synthetic is a waste of $$.... Especially in an oil burning motor

5w20-20w50. Whatever's on sale and new - avoid "recycled oil".
Don't use a cheapy fram filter..
Use a quality filter. Look inside the filter - if you see a metal check valve and fiber element it's probably a good filter. If you see plastic check valve and paper element it's probably junk.
30 minutes of googling will teach you a lot about different oil filter qualities and designs.

The main thing is change it every 3-4k miles and use a quality filter.

Mobile1 - k&n - etc type filters are good but too expensive. The napa gold a quality filter and fair price. Also - the motorcraft (yes ford) filters are great too. Personally I run the motorcraft filter (can't remember part number right now)
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