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Discussion Starter #1
I plan on using the hour meter for determining oil change interval rather than miles. With synthetic oil I plan on doing the change every 125 hours. That would equate to 7,500 miles at a steady 60mph. Any comments/suggestions?
 

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I'm not sure if it's really that critical. The Oil Life Monitor is supposed to consider such things as Engine RPM and speed (which would relate to load on the engine). I'm not sure it's really that smart. I change mine every 5k miles. Probably overkill, though.

I'm sure someone on here can tell you how many hours they have for some large mileage. Then, you can get a more reasonable ratio. Good luck in finding out any additional info.
 

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I don't go by the Oil Life System on either my 2500HD or my Tahoe. I'm doing 5K change intervals on the diesel and 3K change intervals on the Tahoe.


With 33K miles on the Tahoe, I changed the oil and reset the Oil Life System. Then at 36K miles, I changed it again and this time I didn't reset the Oil Life System. At about 36,600 miles the "change oil light" came on. So I'd say that the Oil Life System does some sort of calculation to inform you. This truck is driven regularly to work 15 miles each way. But the thing that bugs me with it and gives me reason to change the oil every 3K miles is that 3 or 4 times a week it goes 3 miles into town, sits for an hour, then 3 miles back home. This doesn't give things a chance to warm up good. Therefore I deem that 3K change intervals are necessary. My guess is the Oil Life System believes so too. At the 39K oil change I will reset the system and then not reset it at the 42K change and see what happens.
 

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Oldman said:
I plan on using the hour meter for determining oil change interval rather than miles. With synthetic oil I plan on doing the change every 125 hours. That would equate to 7,500 miles at a steady 60mph. Any comments/suggestions?
The general guideline with marine (gas) engines is every 50 hours. Personally I would favor a "Gallons burned" interval, not just to be contrary. Hours or miles don't accomodate how HARD. The oil life calculation is supposed to take temperature and revs into account, if you want to be more conservative than that maybe change at 20% oil life left ?

We figure 3 or 4 gallons per hour on the boat. Trucks at 15 MPG and 60 MPH (to make the arithmetic simple) burn 4 GPH. 50 hours at 4 GPH = 200 gallons, 200 gallons at 15 MPG = 3,000 miles. So the 50 hour interval is close (enough) to a 3,000 mile interval - in terms of fuel burnt, which some of us believe determines oil life better than mileage or running time.
BTW, you won't DO 7500 miles in 125 hours areound HERE !
 

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Discussion Starter #6
ArrBee said:
... if you want to be more conservative than that maybe change at 20% oil life left ? ...
BTW, you won't DO 7500 miles in 125 hours areound HERE !

OIl Life? The truck is fairly new to me. I don't reacll reading anything about an oil life indicator. Did the 01 have one?


Where is here? I do 80 miles round trip 5 days a week and average 80 minutes driving time.
 

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I probably overkill as well but both my D-max and inline 6 Trailblazer get oil changes at 5,000. I run the Schaeffer syn blend in both.
 

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Oldman said:
ArrBee said:
... if you want to be more conservative than that maybe change at 20% oil life left ? ...
BTW, you won't DO 7500 miles in 125 hours areound HERE !

OIl Life? The truck is fairly new to me. I don't reacll reading anything about an oil life indicator. Did the 01 have one?


Where is here? I do 80 miles round trip 5 days a week and average 80 minutes driving time.
I don't know which year, or which options/trim package, the DIC is included in. There is a menu item, maybe one or two after "Range" that is called approximately "oil life", it indicates what percentage remains of the last oil change's "life". According to the manual it calculates based on some function of temperature and revs (though it isn't clear if they mean total revolutions or RPMs). Anyway, it CAN take up to 10,000 miles for it to figure down to oil change time - and supposedly it will recommend much more frequent changes if you do a lot of stop/start or city traffic idling.

"Around here" is Massachusetts, about 3 miles from I-495 and a couple more from I-290. With the DIC it can be quite revealing to see what your ACTUAL trip average speed was for trips that you thought were quite fast, e.g. "85 all the way" really translates to "85 once I was on the interstate and up to speed in the fast lane, lasting until half a mile before the exit ramp" getting to and from the interstate kill average trip speed. Toll gates don't help it either )-:
 

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Discussion Starter #10
Bit the bullet and looked in the manual. I don't have a full blown DIC (almost sounds X-rated), but I do have a Change Oil indicator. To reset I turn the ignition to the on position, without starting the truck, and step on the accelerator pedal 3 times. My wife's 4-runner has an info center. I know what you mean about average speed.It takes quite a while at 80 to make up for 5 minutes at 25!!
 

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125 hours doesn't seem long enough. I have 4 FL60 Freightliners with 3126B Cat motors, the engine manual says to change the oil every 500 hours. Iguess it does hold almost 5 gallons of oil though. Seems kind of wasteful to run Dino and change every 3000 miles, which is every 2 months or less. But, hey 4 free oil changes (used within 12,000 miles) from the dealer weren't to be wasted. My bobcats are every 250 hours I think, and they get ran wide open all the time.
 

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Discussion Starter #12
Zsqure, seems to me it was around 200 on the old military multi-fuel diesels with dino oil. Been too many years ago, I can't remember for sure. If the Bobcats are going 250 hours I see no reason why the D-Max, particularly on synthetic oil, can't do the same.
 

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I changed mine for the first time at 10k miles / ~250 hours. It came out looking like it was almost brand new. I'll do the same this time around.
 

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It depends on how hard you work the vehicle and the conditions that it is in.


Farm Machinery which is run usually 95% load all of the time at full throttle is changed at 100 hours or more. The reccomendations now are up to 600 hours on an oil change for some pieces of machinery. We refuse to go past 300 hours though, but regularly go 200-250 on tractors and combines changing the oil once a year with Dino as reccomended. Of course the filters might cost 55 bucks are are about the size of a 2 liter bottle
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My average speed on all my GM trucks has been right at 30 mph. I try and change my oil in my Duramax exery 150-200 hours. or every 5000-5500 miles.


Seems the best to me.


OF COURSE ON ONE TRACTOR, THAT RECCOMENDS 300 HOUR OIL CHANGE INTERVAL, WHICH WE FOLLOW, THEY WILL WARRANTY THE ENGINE FOR 10 YEARS AND 10,000 HOURS IF WE USE CASE IH OIL, FILTER AND OIL ANAYLSIS. Even after 250 hours the oil sample came back normal on the engine oil with an 8.3L Cummins.


Hunter
 

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I use Delo 15-40 in mine and no more than it costs to do 1 truck, I'm going to change mine at least every 5000 miles no matter what. Maybe even sooner if I tow the camper a lot.
 

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While driving home the other day I thought about this. I have almost 16k miles and just under 500 hours on the engine. So, 125 hours would equate to a change every 4k miles or so. That's about half of what you originally estimated.
 

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Discussion Starter #17
tundracamper said:
...I have almost 16k miles and just under 500 hours on the engine. So, 125 hours would equate to a change every 4k miles or so. That's about half of what you originally estimated.

Yes and no. Based on your figures, yes. But I said the 125 hours would equate to 7500 miles at 60mph. That was straight driving at 60. No idle time or city driving. I was just looking for a way to guesstimate an oil change interval.
 

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I just changed my oil at 9975 miles and 276 hours, with 7375 miles on this oil change interval. I have sent an oil sample to Blackstone Labs this morning. Will post results here when I get them. Did not ask for a TBN. Judging by what I have seen from other UOA's, Delvac 1300 should go 10K with no problem.
 

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Oldman,


I did some quick calcs and you should be able to go about 250 hours and be close.


I put about 50 hours on the engine at 1300 miles. Some idling, some highway. A mix of everything.


I think I would start at 250 and adjust accordingly.


My Avg. speed is about 34mph by the way
 
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