Correct oil for the 2004 5.9?

[rbattelle]

The last couple of years, I have been trying to extend the oil drain intervals from about 5000 miles, on up. Each of these oil changes I have had used oil analysis done, which, showed the oil to still be in good condition. One of the last oil changes had over 10,000 miles on it & the analysis said that it was still in good condition. However, when I changed the oil, the engine seemed to be quieter as if the old oil was not lubricating well enough.

Does anyone think that a quieter, smoother running engine is a good indicator that I had stretched the oil change too far?

Joe, I'm no oil expert, but I thought I'd comment.

In my opinion, the thing that "degrades" in old oil is not the lubricity. Rather, the older the oil is the more contaminants it contains. More contaminants frequently means more abrasive particles (although this isn't necessarily true).

This is why, generally, people trust oil analyses. If the additive package remains strong, and the contaminant levels are sufficiently low, there's little reason to change the oil.

Now, what I'm about to say is merely my (assume uneducated) opinion, with absolutely no intent to insult you or your wits. I would ask that you consider the possibility that your mind was playing tricks on you. Similar to the way many people report the factory oil pressure gauge reads higher after an oil change - the mind sees precisely what it expects to see. You expected that maybe you went too long on the oil, so your ears reinforced that belief.

I would expect that if your oil was so horrible as to cause the engine to be noticeably noisier than normal (and let's be honest, these aren't Honda gas engines - they make a lot of noise), that the damage to the engine would be bad enough that even fresh oil wouldn't quiet it down.

The other possibility, of course, is that indeed the engine was noisier with the old oil in it. Well, if it quieted down with the new oil, then I wouldn't worry about it, and for your own sanity if nothing else, change the oil more often than 10000 miles.

In my (admittedly limited) experience, what ends up killing most engines in the lubrication system is the buildup of sludge, as opposed to some lack of lubricity. People go WAY too long without changing the oil, and once the oil reaches its capacity for contaminants they begin to accumulate rapidly inside the engine. Eventually, either a crankshaft oil passage gets plugged up, or the valvetrain accumulates so much gunk that it can't function properly anymore.

I've seen many engines with sludge so thick you literally could scrape it with a putty knife. It has the consistency of mortar or cement. Bad stuff.

Anyway, I wouldn't worry about it. In 400,000 miles you'll wonder why you worried about it.

-Ryan

 

[AH64ID]

Ryan,

I agree. All of my oil changes have been based on contaminants, not the oil itself being done.

I do feel UOA labs are still learning about the effects of soot in modern engines, and I am not going to run my oil as long as I used to.

 

[Grizzly]

My '03, HO 305 HP. has about 85,000 miles on it & I have only used the Delo CI-4+. I bought all they had at Costco & have about 3 cases left. I change oil annually & always use a Fleetguard LF-16035 filter.



The last couple of years, I have been trying to extend the oil drain intervals from about 5000 miles, on up. Each of these oil changes I have had used oil analysis done, which, showed the oil to still be in good condition. One of the last oil changes had over 10,000 miles on it & the analysis said that it was still in good condition. However, when I changed the oil, the engine seemed to be quieter as if the old oil was not lubricating well enough.



Does anyone think that a quieter, smoother running engine is a good indicator that I had stretched the oil change too far? Or, is the used oil analysis a better indicator? If so, why would the engine be quieter with the new oil? Enquiring minds want to know!!!!!!



With that in mind, I've decided to lessen the mileage on the future oil changes to maybe around 7000 miles, or thereabout, for now.



I'd be interested in your opinions.



I found CKelly1's post to be interesting. He's running a fleet of Dodges with some having over 1 million miles on them & changing the oil at 15,000 mile intervals. Since I'll never live long enough to put a million miles on a Cummins, I wonder if the extra noise coming from the old oil isn't doing any damage to the engine? Any thoughts???



Thanks.



Joe F.

Joe,



I compare your thoughts about your engine running quieter with new oil to my thoughts of my car and truck running smoother and quieter after it's been washed. I believe it's our minds playing tricks on us.



After all, if the oil's been changed or the truck's been washed, it has to run better and quieter.



george

 

[rbattelle]

I compare your thoughts about your engine running quieter with new oil to my thoughts of my car and truck running smoother and quieter after it's been washed. I believe it's our minds playing tricks on us.

No, this is established fact. It's how we know cars have a soul.



-Ryan