[Dannyboy18]

I am about 1000 miles out from my next oil change and after reading a couple recent posts I am wondering: is it a good idea to run 10W-40 oil in the summer rather than 10W-30?

Since buying my Jeep in Spring 2005 I have ran standard 10W-30 (no max life blend). Should I switch to 10W-40 to help with the larger clearances caused by higher miles?

I have 151,000 miles right now.

-Dan P.

[XJLI]

I run 15w-40 diesel oil. the thicker the better in my POS motor.

[slvrathlon]

I have run 10w 30, max life stuff... seemed to be ok. But would be interested in hearing others thoughts as well.

[440_Magnum]

Originally Posted by Dannyboy18

I am about 1000 miles out from my next oil change and after reading a couple recent posts I am wondering: is it a good idea to run 10W-40 oil in the summer rather than 10W-30?

Since buying my Jeep in Spring 2005 I have ran standard 10W-30 (no max life blend). Should I switch to 10W-40 to help with the larger clearances caused by higher miles?

I have 151,000 miles right now.

-Dan P.

If you've got good oil pressure and aren't burning oil, there's not any real reason to go to heavier oil. It certainly won't hurt- I run Rotella T Synthetic 5w40 year-round, but I do that mainly because I wanted an HD oil and Rotella T is hard to get in Xw30 weight (you can, but you have to order it- 5w40 is on the shelves everywhere). If I could have the best of everything, I'd run a synthetic HD oil in 0w30 grade.

I did have an oil analysis done at just under 5000 miles on my current fill of Rotella, and the lab said it should be just fine until at least 6000 miles so its obviously doing a good job of protecting my 4.0. All the wear metals were below average for the 4.0:



Whether or not to run a "high mileage" oil is up to you. They really don't help with larger clearances, but most of them have very good additive packages and are much like using a heavy-duty oil. Valvoline MaxLife Synthetic Blend is supposedly very good. Again, unless you're leaking, burning oil, or have low pressure I don't see the need for a high mileage oil.

[Dannyboy18]

My only leak right now is the valve cover. It drips pretty consistently, but I think I will get that fixed this summer when I'm working and have a good amount of cash. All my other leaks have since been fixed.

-Dan P.

[Cherokee2000]

I just put in Amsoil 10w-40 synthetic and Im less then impressed. I was running Total Quartz 9000 5w-40 and it made the engine run quieter then the amsoil does. Either way, I like running a 40 weight, I find it runs smoother and makes up for tolerances.

[xjarchaeologist]

I was wondering the same thing. I have low oil pressure, so I was thinking about switching to 10W-40...I'm interested to hear this one...

[swells]

I run 30w and lucas It runs quieter I have 181.000 miles dosent burn oil yet.

[94HOCHEROKEE]

Recently I went to a Penzoil training class for my job and good ol' Wal-mart tire lube express, and they were saying how 5w-30 is better protection for cold/dry starts, and runs through your engine faster making it run cooler...? It also creates less sludge in your engine. It was news to me cause I thought the heavier weight 10w30 would be better protection all around. Thinking of running 5w30 instead of 10w30...... I use the Val. Max Life Full Syn and I have no complaints.

[440_Magnum]

Originally Posted by 94HOCHEROKEE

Recently I went to a Penzoil training class for my job and good ol' Wal-mart tire lube express, and they were saying how 5w-30 is better protection for cold/dry starts, and runs through your engine faster making it run cooler...? It also creates less sludge in your engine. It was news to me cause I thought the heavier weight 10w30 would be better protection all around. Thinking of running 5w30 instead of 10w30...... I use the Val. Max Life Full Syn and I have no complaints.

Its true. You really should probably run the thinnest grade that still gives good oil pressure. Like I said, I really would like it if Rotella had a 0w30 grade, but they don't. Jeeps do "like" their oil a little heavier than other engines, so a 5w40 is about right for them. But you'd never catch me running something like a 15w50 or 20w50.

[colt933]

The owner's manual states 5w30 in really cold climates and 10w30 as universal. Both are the same after it warms up.

[XJLI]

Originally Posted by 440_Magnum

Its true. You really should probably run the thinnest grade that still gives good oil pressure. Like I said, I really would like it if Rotella had a 0w30 grade, but they don't. Jeeps do "like" their oil a little heavier than other engines, so a 5w40 is about right for them. But you'd never catch me running something like a 15w50 or 20w50.

My jeep drank all 6qts 5w30 this winter in 2 months. these motors are almost 50 year old technology.

[paroxysym]

Xjli what brand oil are you running again in a 5w-40? I'm at 112' and she burned about a qt of 5w-30 between oil changes. Would like to go with something I know she won't burn that much but still provide protection and proper lubrication.. That's why I'm curious about the 5w-40 in summer?

[XJLI]

Originally Posted by paroxysym

Xjli what brand oil are you running again in a 5w-40? I'm at 112' and she burned about a qt of 5w-30 between oil changes. Would like to go with something I know she won't burn that much but still provide protection and proper lubrication.. That's why I'm curious about the 5w-40 in summer?

castrol diesel 15w-40

[sskinner]

hey I have noticed my oil pressure drops down to 15 to 20 psi once it warms up at idle and will hold a soalid 40 psi under load is this normal?