Did a search and really didn't find the info I was looking for. I'm right at 3000k on the new X and was wondering if you guys had some suggestioins on the type that I use. I'm not a big believer in the syn. My question is that I pull a 2500 lbs boat trailer frequently and was wondering if a specific type would be easier on the X. usually put in 10w-40 during the summers here in TX. Any suggestions?

New_X_O,
Man, I'd think you have the perfect application for a synthetic oil...high ambient temp, and a work load. I don't think I'd run 10w40 though. I'd suggest that the protection you're looking for would be better found in a synthetic 5 or 10w30 as opposed to going to a higher viscosity.
So why aren't you a fan of synthetic oil? The cost? Well, you can run an extended drain interval with it...Are you concerned about old wives tales about leaking seals? I haven't seen anything like that.
I'd say, for the average driver, regular oil changes offer enough protection. However, if you're towing in high heat...get the best you can.
Now, your truck is also new enough that the tranny and diff fluids shouldn't be a problem, but I'd consider running synth in them as well down the road.
Bogatyr

Seconded.

In my mind, hot temps and towing = Mobil 1 10w30. If it gets down to 40 degrees or less in the winter use 5w30 then. Change every 7500 instead of every 3000 to offset the higher cost of the oil, if that's the concern.

Or just use a good quality dino oil like Castrol (same viscosity advice as above) and change every 3000, it's up to you. You'll find a million opinions on oil here, just do whatever floats (and tows) your boat!

Cost is such a pointless argument with synthetics unless you're REALLY stretching your paycheck. An extra $15 an oil change isn't going to break most of us here.

Brent

I tow my 4500# boat with my SC-X, regular mineral oil, no problems at 26,000 miles. The oil is still reasonably clean at 4000 mile O.D.I.

BTW I tow here from the LA area, which is uphill any way out of the basin and frequently over 90'F.

10w40 should be sufficient, and it doesn't matter if you like Synthetic or not, there are many guys in the heavy-duty field that triple O.D.I. on mineral oil (using oil analysis) and are not seeing adverse effects (at 1.3 million miles).

O.D.I.=Oil Drain Interval

I'm trying to extend my oil changes, but I'm finding that without proper oil testing it's not a good risk. At least check it the first few changes to see how the synthetic is doing and increase the interval slowly...

BTW - this can be done with normal oil too... synthetic isn't the only oil that you can push limits with.... and for really long intervals, the weak link becomes the filtration, not the oil.
-=RB

That's why you still change filters at reasonable intervals, testing at the time of oil filter change each time, as trend analysis is more important than once-in-a-while analysis...

Had to revive this topic, cause I just got my analysis results in from Blackstone-Labs.com. Looks pretty good according to what they show, for an engine with 11K miles on it (3750 on the oil, which was my first change with Mobil 1)... all the numbers were pretty much at or below the averages except boron and calcium. They don't see any issues, and the flashpoint is still up around 415 degrees, as well as viscosity holding up well. (no antifreeze or water either, and fuel % is .5% - which is great.

I'm looking for extending the intervals, so I did the extra TBN test as well.. all in all it cost me $30 or so, which I don't consider bad considering how interested I am in my engine and how valuable this info could be if I was having problems.

Considering their suggestions, I'm bumping up my change interval around 33% to 5000 miles before the next test. And by this oil test it looks like I've still got life, the old Mobil one is going into the garden tractor - not the recycle bin. I paid for it - might as well use it fully!

They will send you a free test kit if you hit their website - www.blackstone-labs.com . Read the FAQ also - and print that hazzard letter for the post office to read - they gave me a hard time when I tried to ship it but eventually took it.

Happy testing!
-=RB

RB42,
Do you have the full results? What was the TBN? Certainly, if the TBN is good I don't see why you can't go 5000 or more miles.
Since I just changed my oil, I'm hoping to send the Xterra's first batch to Blackstone in the fall or when I reach 4-5k. I'm currently running Schaeffers 5w30 synthetic blend in the sump.
What you may want to watch is the molybdenum number as some oils have more of it than others and it's the "secret" ingredient in many of those "high mileage" oils out there with the notable exception of Valvoline MaxLife.\
Bogatyr

Got the full report as a PDF today, but it's got some personal info so I hesitate to post it..

TBN was 3.2, and the only items that were different than the universal average were:
Boron - 109 vs avg 67
Calcium - 2911 vs 2155 avg
Magnesium - 26 vs avg 295

I can see the magnesium being less if internal parts used in the VG33ER engine are made with less Magnesium alloys (magnesium's kind of soft, isn't it? But lightweight.)

Not sure what the Boron and Calcium mean, but they didn't see any issues with it.

-=RB

EDIT - Boron Calcium and Magnesium are listed as disperants/detergents, so I'm thinking Mobil 1 uses more calcium/boron in it's detergent additives than other oils that use magnesium.. I guess.

RB42,
Understood about the personal info.
Did you think that TBN was a little on the low side for that many miles? I would be interesting to see what it looks like at 5k.
Sounds like your guesses regarding the boron/magnesium/calcium are right...I'd just keep an eye on the calcium number as well though as it's often in water...but if they didn't find any glycol, it shouldn't be a big deal...
Bogatyr