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new to my 04.5 dmax and was wondering what oil to start using. i've done 2 changes so far and used 15w40 valvoline premimum blue( which is what a buddy uses in his cummins, w/ no problems) and ac delco filters. i go 5k between changes. i guess i could go farther between changes if i used synthetic? was also wondering if it would be safe to go to 5w30. i do some heavier hauling during the summer pulling loaded haywagons and other farm eq. i know during the colder months the 5w would be ok. in my gasser i always used synthetic and it was great. we also use synthetic in my dads vw tdi w/ well over 100k and its great in that.just wondering about the dmax and what everyone uses. thanks in advance jim
 

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AMSOIL HDD 5W30 or AME 15W40 and an Eao oil filter. 15,000 mile interval under severe service. You'd be fine running the 5W30 diesel oil. It isn't a 5W30 gas engine oil at all.

If I can be of further assistance, let me know!
-Chuck
 

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you could go 20,000 between changes, but you need bypass filtration and an oil cooler if you use the truck for towing. The Fram filters have been known to fail, and are inferior quality generally, so stay with ac delco, bosch or baldwin, to name a few good ones.
 

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Don't use the HDD 5W30 in your LLY. I strongly feel that the lower viscosity oil yields lower oil pressure, and the LLy trucks occasionally have that overheating issue, which is combimed with low oil pressure. For the sake of the motor I stongly suggest the use of the Amsoil AME 15W40. It is a durable oil and will not change your oil pressures, and has the terrible side effect of increasing fuel mileage!:drink
 

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What are the oil filter numbers for the ac delco, bosch or baldwin filters? If you know them off the top of your head?
 

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What are your opinions of Rotella? We have used that for our heavy-use trucks (fire apparatus) around here for years - but then again, these are "big" diesels.
 

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Here in Alaska, I know big truckers usually put in Rotella T. 1. Is because of the good quality and 2. is due to the large amount of oil it takes and the reasonable price. If they trust to run their trucks on something up here it is usually because it does really well even when it's cold but may switch to the 5W instead. I have it in my pickup and it still looks clean, like I just put it in yesterday. I guess it's all about preference, budget, your environment and what you do with your truck.
 

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I just today switched my 2007 Classic (15K miles) over to Amsoil 15-40 and Wix filter. I immediately noticed a drop in pressure. Before the Amsoil at 1500 RPM the pressure was just barely under the 60 mark, now it is down 2 ticks. also now below 30 at idle.
 

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That is not a problem.

High oil pressure is a bigger problem than low oil pressure, because it signifies lower oil volumetric flow rate.

I would not hesitate to use 5W-30, or even a 0W-30 in the winter, though it is not on the GM oil list. There are fewer heat sensitive viscosity improvers, a good thing. I would be concerned if 2000 rpm pressure fell below 30 psi, if under heavy load.
 
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