Engine oil

[Hulk5T]

Is it ok to change to 15-40 pure synthetic oil in my 8.3 Cummins ?

 

[Elk1111]

It’s not going to hurt anything but your wallet.

 

[simp5782]

Is it ok to change to 15-40 pure synthetic oil in my 8.3 Cummins ?

15w40 synthetic is hard to find. Usually only by Lucas.

5w40 synthetic is more common which will make it rattle.

 

[G744]

Synthetic blends, such as the Rotella offering are the deal. Wear characteristics are excellent, and the price point is good.

You may never run an engine long enough to see it's end of life, but from my personal experience in Mercedes Turbodiesels it has really made a difference in wear, especially with the timing chain.

The standard was check the chain for rotational stretch every 100K, at which time it usually went to 6 degrees and was time for a new chain. So far (after a full rebuild) one of mine has accrued 348K with NO stretch.

So if your fav motor has a wear point that you can measure easily, give it a try.

DG

 

[98G]

Is it ok to change to 15-40 pure synthetic oil in my 8.3 Cummins ?

You're almost certainly going to time out the oil before you wear out the oil. Thus the extended drain interval on the synthetic doesn't really help you.

My opinion, with a history of being nearly OCD on oil selection, is that the best choice for diesel MVs is any decent oil (I use Rotella 15w40) changed frequently.

 

[KN6KXR]

The best oil is lots of good oil changed on time with new filters every time.....

If you are concerned I suggest getting Blackstone Labs to send you some free UOA (used oil analysis) kits. When you change the oil you take a sample and drop the prepaid envelope in the mail. Costs $30 for the basic analysis. If you still feel the need to get spendy on your oil then go ahead and run the fancy stuff then do a UOA again and compare. If wear particles remain the same it's a waste of money. I just did this had Rotella in there with about 4k miles will post results when I get them.

I'm running "Kirkland Signature" (aka Costco) 15-40 they had a great deal better than I could get locally in bulk (16 gallon drum). It's probably re-branded Rotella or similar. I'm picky about my filters Wix/Napa only. YMMV.....

 

[G744]

+ on that Costco oil for value.

DG

 

[Crf450x]

15w40 synthetic is hard to find. Usually only by Lucas.

5w40 synthetic is more common which will make it rattle.

Rotella makes a synthetic 15w40. I use it in my dirt bikes.

 

[simp5782]

Rotella makes a synthetic 15w40. I use it in my dirt bikes.

Like I said. It is hard to find. You might find 1 or 2 of them but doubtful you are going to find 8 to 11 gallons of it at one location. Napa carries usually 2 cases of Lucas 15W40 as it is a common stock for them.

 

[chucky]

And IMHO if its a CAT motor put CAT filters on it dont be cheap on this part !

 

[Micmada]

You're almost certainly going to time out the oil before you wear out the oil. Thus the extended drain interval on the synthetic doesn't really help you.

My opinion, with a history of being nearly OCD on oil selection, is that the best choice for diesel MVs is any decent oil (I use Rotella 15w40) changed frequently.

I stay away from Rotella due to the low emission ZDDP content that at one point was destroying the cams on Ford 6.7s. Im not sure since then Rotella changed the formula but I do remember that Chevron had to discontinue one of their diesel oils that I bought $20 for 5 gal once at walmart because their zddp was way too low. I simply added $5 worth of Zddp in each and was good to go

I stick with Delo for this reason. Also synthetic going into your pistons for whatever reason will hydrolock while regular oil will burn some. So for safety reasons I am iffy on synthetics.

If you want high peformance and good zddp go with Amsoil or even better Schaeffer race oil. Ford branded Motorcraft red bottle diesel oil is good too and came out after there were issues with low zddp oils destroying 6.7s

 

[Micmada]

And IMHO if its a CAT motor put CAT filters on it dont be cheap on this part !

I thought that Napa/Wix filters were the best after seeing a test but when Adeptape on youtube opened them and showed the crappy worksmanship of their regular white cannisters I was horrified.

I wish I could find Mann filters for my M923 if anyone knows which model it is. I tried looking but no bueno so far. Are cat filter proprietary and not fitting cummins?

 

[juanprado]

Napa, carquest, are made by wix.
Same stuff.

 

[chucky]

I thought that Napa/Wix filters were the best after seeing a test but when Adeptape on youtube opened them and showed the crappy worksmanship of their regular white cannisters I was horrified.

I wish I could find Mann filters for my M923 if anyone knows which model it is. I tried looking but no bueno so far. Are cat filter proprietary and not fitting cummins?

You will have to cross your cummins filter number over to see if Cat makes anything to fit it or cal a big truck parts counter and see if they can cross it ! AFSI makes 80% of all Cat filters see if they make filters for your cummins .