Oil Change Interval

[bhelms22]

I've been reading up on extended oil change intervals for synthetic oil, most of what I find is for the Duramax. We have 2 Duramax trucks at the shop and they do not seem to dump as much soot into the oil as our 6.5L diesels.

I usually run Delvac 1300 and change every 3500-4000 or so.Next oil change I am going to try to fit on a Duramax oil filter and go to Rotella 5W-40 synthetic. Just wondering how many miles yall run your synthetic oil and how the little extra volume might help?

 

[Burning oil]

I just put Amsoil oil and filter in my Titan I want to see if I can go 25000 miles on it. I will do oil analyisis after 15000 miles. On the diesel I would think 15000 miles easy, but don't have the "official" word on that. I can check if you like?

 

[bhelms22]

I can check if you like?

If ya wouldn't mind that'd be good. I might consider Amsoil if it could go that far.

 

[Burning oil]

It'll be tomorrow.

Rough math: 25000 devide by 3000 = 8.333. times 8 quarts = 66.6 quarts and 8 filters as opposed to using 8 quarts and 1 filter in 25000 miles sept for any topping off. Blows my mind when I think of it that way. The cost is way cheaper in the long run.

 

[WarWagon]

Ruining hard I am not afraid to go 10,000 miles on regular oil in the Duramax and have oil analysis to back it up. On the 6.5 running hard 3K was pushing it and the 1993 owner's manual calls for 2500 mile oil changes!!! (Ever get a phone call from an oil analysis lab and, yes, it WAS bad news!)

The gapless rings I am using make a night and day difference that you can see in the 6.2 oil. I have not gotten an oil analysis off that engine, but it would be interesting. The oil looks like it is in a gas engine as you can see the dipstick through the oil at 3K. (Yes, I posted pics.)

IMO the 6.5/6.2 is a really dirty engine as far as what gets dumped in the oil so taking it out for longer intervals would require oil samples at the minimum. If you are driving it easy maybe it is cleaner. But the amount of soot buildup I have wiped off 6.2 push rods has been 1/16 of an inch thick!

 

[Jorge6.5]

Whats this talk about using a duramax oil filter? What years will work on the 6.5 and how much more capacity are we talking about here? will one of these duramax oil filters even fit on a 6.5?


Thanks

 

[bhelms22]

IMO the 6.5/6.2 is a really dirty engine as far as what gets dumped in the oil so taking it out for longer intervals would require oil samples at the minimum. If you are driving it easy maybe it is cleaner. But the amount of soot buildup I have wiped off 6.2 push rods has been 1/16 of an inch thick!

That is what concerns me. I have next to no blow-by on my K2500 and the oil is filthy after one trip to down and back. This truck is usually just a daily driver but when it tows it tows fairly heavy. Mostly farm equipment, trucks and scrap metal.

Whats this talk about using a duramax oil filter? What years will work on the 6.5 and how much more capacity are we talking about here? will one of these duramax oil filters even fit on a 6.5?

IIRC the Duramax filter will squeeze in on 6.5L 4x4's and hold about another quart of oil. Looking at the size of the Duramax filter specs beside those of the 6.5L on the WIX website IDK if it will hold that much more. I figured I'd try it and see how much more it holds if I can fit it on. As far as I know all the Duramax trucks use the same filter, someone correct me if i'm wrong.

 

[DennisG01]

Using Rotella T6 0-40 (maybe it's 5-40) synthetic, I ran about 8,000 miles. I then got an analysis and they said they didn't like some of the numbers, but since the new engine still may be breaking in, that could explain it. They said to check back in 4,000 miles. I did and they said things were looking better, but do another test in another 4,000 miles. I'm getting close to that, now. After this next test, they will start to recommend an extended interval for me. Being able to run an extended interval is not the main reason I'm doing the tests, though. However, I thought it would be interesting to know what I could do, if I wanted to.

Recommendation... don't do an extended interval without first establishing a baseline by using a few oil analysis.

 

[Burning oil]

OK Amsoil "Heavy duty diesel and marine" 15-40w is rated at 3 times OEM intervals, so thats 7500miles if 2500 is recomended. You should be able to push that out even further with a good bypass filter set up.
On a Dmax I seem to remember 10,000 as the OEM recomended that would give 30,000 with the Amsoil.

Dennis had a good point, get an analyisis done now to compair to later.

 

[WarWagon]

Oh yeah, the Duramax has 3 gallons of oil in it, 12 quarts. The 6.5 has ~6 or 7 depending how much the cooler drains. This has a big effect of how much soot the additives can handle - double the additives in the dmax by capacity... Dirt that can be filtered is separate from additive life, both limit oil life. But looking at it by quart it is still 2 times the life. 12 quarts goes 5000 miles in a 6.5 changed at 2500 miles...

The 2008 Dmax oil change monitor/light number in the computer is just shy of 10,000 miles for ideal conditions. Several factors reduce life like sustained high temp, fuel burned, etc. The reduced life by the computer was bang on with the UOA I did.

 

[Big T]

The other problem is that the 6.5TD typically burns a quart every 2500 to 3000 miles. So if you try to go 10,000 miles, you've had to add almost 50% of it's oil capacity to get there. So it isn't 7 quarts for 10,000 miles, it's more like close to 11 quarts. As you add, the concentration of soot in the remaining oil grows. Kinda like reducing a sauce on the stove to thicken it.

I'm running Rotella T6 5w40 right now and am at 8,000 miles and thinking I'm going to change it the next time it gets low on the stick.

 

[great white]

The other problem is that the 6.5TD typically burns a quart every 2500 to 3000 miles...

Well, that's as much a function of engine condition as anything else.

My optimizer has just over 11000 kms on it from new.

If the level drops between changes (after break in was complete) it's imperceptible.

Engine condition also has a lot to do with how fast your oil becomes soot ladden.

Worn rings and cylinders let more combustion products past.

My optimizer goes past 1000 kms before the oil begins to become opaque. You can still see a bit of "gold" but by about 1500-2000 kms it's pretty black.

I've often thought about buying another oil pan and kicking it out on the sides of the sump as much as will fit to increase oil capacity to that of a "proper" light/medium diesel (ie: 10-12 liters)

 

[bhelms22]

The other problem is that the 6.5TD typically burns a quart every 2500 to 3000 miles. So if you try to go 10,000 miles, you've had to add almost 50% of it's oil capacity to get there. So it isn't 7 quarts for 10,000 miles, it's more like close to 11 quarts. As you add, the concentration of soot in the remaining oil grows. Kinda like reducing a sauce on the stove to thicken it.

The only reason I am considering synthetic is because my truck does not burn enough oil to speak of. Over 4,000 miles it barely drops enough to notice on the dip stick.

 

[Brooklyn Tow]

Mobil1 oil filters for the 6.5 and the 6.6 (D-Max) are the same size M1 302 for the 6.5 and M1 303 for the 6.6 (D-Max) (Numbers might be one off; 301 and 302)

All the other 6.5 filters are about a 1.5" shorter than a D-Max filter.

 

[btfarm]

Oh yeah, the Duramax has 3 gallons of oil in it, 12 quarts.

It's 2 1/2 gal. (10 qts).

All highway driving will send the oil life upwards of 9500 mi on an oil change for a DMax. I change regularly at 6-7.5k but a couple of times I've seen close to 10k before I had a chance and the oil life monitor had still shown over 10%.
Even on a DMax though, the oil is black by about 1500 miles. Using 15W40 Rotella dyno. I've never had a UOA done.

 

[THEFERMANATOR]

Like stated above, a DURAMAX holds 10 quarts(4500/5500's may be 12 as they have a differrent pan set-up). Factory reccomended drain intervals on them up to 05 was 7500 when the light comes on, 06+ can go as high as 16K though before the light will come on. I change mine out at 10K using the ROTELLA T6 5W40 oil. It isn't bad, but a bit dirtier than I would like. Then again my BURB is either hauling a trailer, or getting the snot flogged out of it as I don't drive it much and like to PLAY when I do drive it:hihi:. I know on my 6.5 I changed it out at 5K miles using 15W40 ROTELLA, and it always came out looking nice still and wouldn't be down but maybe a cup in 5K miles(I tried CASTROL diesel oil and it used a quart every 1K miles). The DURAMAX filter will drop right into the 4X4 6.5's, and holds about a 1/2 quart more oil than a standard 6.5 filter(which is also the same filter that was used on GM small and big block engines for years and years), and is fully capable of filtering anything teh 6.5 can throw at it as it is a high flow media filter.

 

[bhelms22]

I am partial to WIX filters. The 6.5L and Duramax specs are below:

6.5L
Height: 5.178"
Diameter: 3.66"

6.6L
Height: 5.216"
Diameter: 3.69"



Is there a bennifit in the WIX 6.6L vs the 6.5L, because the Dmax filter is twice as much around here. Is this 6.6L filter small or is the 6.5L filter big?

 

[WarWagon]

I forget I run the 2 quart Killerbee oil cooler. That is where the extra 2 quarts go when I dump in 3 gal to get it to the full mark. :doh: The 10K mark was a field in the HP Tuners for the 2008 Oil Monitor. Not sure how accurate HP Tuners would be, but, this was the high mark for our oil changes.

I would be curious if the 6.5 oil use rate goes down for synthetic. Low mile engines and old worn out and leaky would use 1 quart every 500 miles towing. Literally a quart every day and an oil change every week. I think it boiled off or was sucked out the CDR, even a new CDR did not help. And it would go down 2 quarts if I overlooked it one day so not a bad dipstick reading...

 

[great white]

Brand new optimizer and rotella synth here.

As I mentioned, oil usage is not noticeable oil change to oil change.

My worn out 599 block was a different story. At least a liter between oil changes.

 

[racedaymechanic]

Brand new optimizer and rotella synth here.

As I mentioned, oil usage is not noticeable oil change to oil change.

My worn out 599 block was a different story. At least a liter between oil changes.

Mine has not dropped a noticable amount between changes either, I run The 5 w 40 Mobil 1 Turbo Diesel Oil and a Wix 51060 Racing Filter The price is right on them (free) I run about 4000 miles between changes and the oil is not Terrible Black, I cut every filter and look at the media under a good light