The Haynes and Chilton repair manuals recommend the use of conventional 10-w30.

 

I love these oil question cause so many of us use so many differed weights and grades. For winter we can use 5w-30 but I've ran that throughout all last year with no burn off. I'm running 10w-30 this year but there isn't to much difference. As for synthetic, some ppl will tell you if you've never used it before to change oil again at 1500-2000 cause you might get loose sludge. And yea you'll get some oil spill out your top, happened to me after I switch to syntec. Mechanic one time last year tried to convince me to redo engine etc etc. Year later, and several oil changes, I don't lose oil, or pressure. Well I fess that's the end of my rant hope some of it made sense

 

About fifty fifty if it's all highway it's more like 22 if my ladders not on. I have put these miles on since september 2010. I average 5k a month for work so I keep really good track of my mpg cuz every mile I can get makes me more money.

 

I also run amsoil fluids in transmission,diffs, tcase,coolant, and power steering

 

I've just recently seen that amsoil. I've never seen it in NYC before. How is it

 

I now swear by it. Cost me about a hundred bucks Avery 25 k miles for my oil change. Way cheaper if ya run the miles like me. Oils still a honey brown color after over 20 k on it. It's 25 k or one year guaranteed

 

Hmmm good to know

 

Synthetic won't hurt your jeep, heavier on the wallet.
This is what works for me. 10w-30 of a name brand, not a cheapest no name.
Fram filter, never had a fram problem in over 40 years.
Change every 7000 +/- 1000 km (say little more than 4500 miles)
Had lots of vehicles last lots of miles.
Gotta say the current 4.0L Renix is king. 508000 km (just under 315000miles)
Sure it leaks a lot, sure I've replaced all the seals and gaskets, (still leaks). Thing is I run easy 1000km/week. Don't smoke or burn oil, plugs are clean, no sludge buildup. Engine runs fairly strong, definately no spring chicken and cylinders have blowby as indicated by the crankcase pressure. Oil pressure is 63 psi when the oil is fresh, drops to 40-45 psi when oil is done (7000km). Have applied 1/2 to 3/4 liter of Lucas in the mix from time to time. Top up about 1/2 to 3/4 liter oil at about 5000 km. Always drips when parked. Oil on floor pans.
My bottom line is standard oil and filter changes regularly. Works for me.

 

You're a real trooper with your girl . I was pleased when I changed to mobil 1 high mileage full synthetic and I'll use the high capacity filter. If I let her go over on an oil change she never complains. Plus I get the oil at walmart so it's pretty inexpensive compared to auto zone etc