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Conventional vs Synthetic engine oil

5K views 11 replies 7 participants last post by  NMDuramax 
#1 ·
I'm sure this horse has been beat before, but I want to beat it a little more. I have used Rotella 15w40 since this engine was new. It now has 65,000 miles. No issues of any kind. I'm switching to Amsoil in my motorcycle and considering Amsoil in my Duramax. I welcome any thoughts/input on this. I pull a 20,000 # 5TH wheel 6-8,000 miles per year. Otherwise just used for transportation
Would it be a bad idea to switch to synthetic at this time?

Thanks, Tim

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#2 ·
Never a bad idea in my mind.
 
#3 ·
Nope. Womt hurt anything.

The duramax motors arent picky on oil. Pick a good oil you trust and use good filters.

I run amsoil signature 15w40. Will go to 5w40 this winter.

I also upgraded to a larger Donaldson filter. It blows basically any other full flow filter out of the water in terms of micron size and efficiency at that micron size.

Not my pic, just reference. All you need is the filter and the new adapter. Also adds an extra 2 quarts of oil capacity.
 
#6 ·
19trax95 said:
All you need is the filter and the new adapter. Also adds an extra 2 quarts of oil capacity.
I see that PPE has a similar filter where no adapter is needed: https://www.ppediesel.com/shop/premium- ... ilter.html

I haven't tried one of theirs yet, but may in the future.

They say the features are:

Direct replacement for the stock oil filter - no adapter!
High-efficient 5 micron filtration
Bypass is 10 PSI over OEM
Filter increases oil capacity by one quart
900 sq. in. of accordion-folded nylon and fiberglass media
Perforated metal core and spiral-wrapped adhesive secures filter media
13/16-16 UNF threaded baseplate with 120% larger passages
Twice the surface area, filtration and filter life
Compatible with conventional and synthetic oils
 
#8 ·
19trax95 said:
Nope. Womt hurt anything.

The duramax motors arent picky on oil. Pick a good oil you trust and use good filters.

I run amsoil signature 15w40. Will go to 5w40 this winter.

I also upgraded to a larger Donaldson filter. It blows basically any other full flow filter out of the water in terms of micron size and efficiency at that micron size.

Not my pic, just reference. All you need is the filter and the new adapter. Also adds an extra 2 quarts of oil capacity.
Question. I currently use Royal Purple 15W-40 full synthetic, and I want to switch to Shell Rotella T-6 15W-40 (T-6 is full synthetic). I was talking to a diesel mechanic about it, and he said that switching brands can cause sludge build up due to the different oil detergent formulas. Have you heard of that issue before. I could see the sludge build up becoming an issue due to not changing oil when needed, or due to heavy work loads, but just switching brands? I'm at 142K on miles, and have been using full synthetic since around 40K, prior to that was using the original synthetic blend from the dealer.
 
#9 ·
Never have I heard or experienced that.

Using good oils and regular change intervals, it doesn't matter much what oil you pick and what you switch to as long as it's all quality stuff. Rotella, especially the T6, is probably the industry standard oil for the heavy duty market.

At my shop we offer T4, T5, and T6. Most customers we have go with the T4 and change it a little more often. Some of the long haul guys use T6 and swap filters in between oil changes. All depends on their needs.

But you will be just fine doing what you plan to do.
 
#10 ·
19trax95 said:
Never have I heard or experienced that.

Using good oils and regular change intervals, it doesn't matter much what oil you pick and what you switch to as long as it's all quality stuff. Rotella, especially the T6, is probably the industry standard oil for the heavy duty market.

At my shop we offer T4, T5, and T6. Most customers we have go with the T4 and change it a little more often. Some of the long haul guys use T6 and swap filters in between oil changes. All depends on their needs.

But you will be just fine doing what you plan to do.
Awesome! I appreciate the info, and confirmation. Grease Monkey was charging me an average of $150 per oil and filter change. I can do two myself for that price. I will go out and pick up some of the Rotella T-6. Advance has it for $60 for the 2 1/2 gallon jug, and I have $20 in rewards points, so bonus. I already have the oil filter, picked up the Mobil 1 M1-303A.
Thanks Again
 
#11 ·
Check some heavy duty diesel shops as well for oil. We buy it in such bulk that we can sell it cheap. I don't recall off hand the cost of the stuff at work but we sell it by the gallon jug, 2.5 gallon jugs every now and then, 5 gallon buckets, and 55 gallom drums. We sell a good amount of the drums.

Over on the duramax forum there is a member who took the time to cut open, take pics, and explain most of the filters, both fuel and oil, for these motors.

It's a really nice thread and interesting to see how poor the quality of some of the supposed top teir filters are.

Unfortunately the mobil was pretty bad. In many examples from different batches, had a TON of excess glue all over on the inside of them.
 
#12 ·
19trax95 said:
Check some heavy duty diesel shops as well for oil. We buy it in such bulk that we can sell it cheap. I don't recall off hand the cost of the stuff at work but we sell it by the gallon jug, 2.5 gallon jugs every now and then, 5 gallon buckets, and 55 gallom drums. We sell a good amount of the drums.

Over on the duramax forum there is a member who took the time to cut open, take pics, and explain most of the filters, both fuel and oil, for these motors.

It's a really nice thread and interesting to see how poor the quality of some of the supposed top teir filters are.

Unfortunately the mobil was pretty bad. In many examples from different batches, had a TON of excess glue all over on the inside of them.
WOW! I'll have to hop over to the Duramax forum and check it out. I still have my receipt for the Mobil 1 filter. :lol:
Thanks for the heads-up.
 
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