what kind of oil in motor ?

Rotella. Use it in my pick-up also.

 

Mobile delvac is what I run in ours. 15-40 summer and winter they run 24/7 in the winter so no need to worry about molasses in the pan when starting. Change every 8k-10k in the winter and every 10-12k in the summer. I don't care for rotella have had too many problems with it foaming up in my pickup and that only runs about 50lbs of oil pressure at cruise rpm. I don't trust it at 70lbs in our cats but that's me. I have heard a lot of people love it personally I'd rather save a few bucks and run my mobile delvac love that stuff and I can pull the dipstick right after shutting it off and never see an air bubble.

 

I would try this Castrol Elixion synthetic, they guarantee 4% fuel savings, but I can't find it , only the blend for gas engines.
http://www.castrol.com/castrol/sectiongenericarticle.do?categoryId=9045281&contentId=7079765

 

the whole time i've been driving this truck. i never got above 5.2.

yesterday i changed to mobil. and averaged upper 7s today. but the future is still to be determined. the truck i drove last year. always got 3/4 mpg better with mobile.

oil may be oil. but when it comes to the isx motor. there's only 1 that it likes. you can tell when it's not mobile cuz it always sounds like a tank.

 

Well I had a pm done on my international prostar 2009 yesterday at Speedco out of West Memphis Ar. I used rotella. I did not get oil samples. I will in 15, 000 mile later. I plan on doing a pm every 15, 000 miles. I have a cummins isx 435 hp. Its performs at about 390 hp when I had the engine diagnostic performed. I laso had my rear and front differentials checked with oil added. Transmission was level was ok. Im a new owner and I must say I was a little ill prepared because I didnt know whoch was the best oil. Nor did I have the cash in hand for oil samples.

 

Delvac 15/40 year around. I live in East Texas so it always HOT

 

i pay close to $300 everytime i change oil.

albuquerque charged me $450 one time. i'm like WTF. had to show them my previous reciepts. they said price of oil filters went from 7 to 60 a peace. no other TA has tried that trick.

 

I prefer 5 40 fulllsnyethic,all year round,why ,you could tell when are on steep hill.it pull better than 15 40 oil.i change it every 13000, the next 13000 ,I change the oil filter,fuel filter.then 3rd time I change everything,the first 13000, u will get good mileage.it cost me $290 4 the oil,$100 oil,fuel filter,and the labor $80, so I paying around $500 dollar,u do the math,am cheaper than other guys,2 oil change cost in truckstop,$600, my advantage to other driver is a have. Fullsynehtic oil,I check my oil sample in speedco ,every 100000, just like new mother,highly recommend 5 40 mobile 1, I used in my automobile

 

Schaeffers 15-40 Supreme 7000 year round. It's there SynBlend oil. I get "free" oil samples with a purchase of a 55 gallon drum. I'm at 50k miles with NO bypass system.

Here's my take on oil......it's the blood for your engine. Sampling is critical. Price isn't an issue for me. I'm paying in the mid $20's/gallon for the Schaeffers. There are a couple of shops that have Schaeffers here in MN and WI. I buy my oil from a Rep. Here's where I feel the real value is. I get someone who knows oil, has access to folks who know oil (Schaeffers is the oldest oil company out there), has a data base of history with regards to my particular engine(s). Ask that of your local shop, Speedco, etc. Why would that matter? Have an engine go down. One of the first things the shop is going to blame is the oil. Especially if they haven't done the oil changes. Schaeffers will back the repairs if, in fact, it was oil related. This is where oil samples and a history are important. Will Shell, Delo, Mobil do that? You may say access to a "Designer" oil is way to limiting and too costly. Really? It's all about priorities. You'll go out and spend tens of thousands of dollars (maybe $100's of thousands) on equipment then go cheap on oil?

 

This is like asking if blondes or redheads are hotter... its all opinion.

I say redheads.