OCI on company truck

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Jan 17, 2003
9200' Colorado
I need the expert opinion of all my fellow oil junkies here on BITOG. Application is a 2003 Chevy 2500HD 4x4, 8.1 Allison. I bought it a few weeks ago with 27k miles on it. I immediately did a full fluid and filter service. In 1600 miles so far it has used about 1/3 qt which is great for this motor. My one bad vice in life is that I can't stop my addiction to home brewing my own oil combinations. I know what many of you think about it but when I try to stop I can't. Is there a 12 step program in my future?

Anyways, 90% of my summer driving is at speeds of 70-80+ mph, cruise and AC on high, interstate hwy, open road driving. On the way out I hit a low temp of 45 at night in the Rockies and a high of 115 just outside of Death Valley. While making sales calls in So Cal it has been lots of 85+ degrees bumper to bumper traffic with the AC on high. But like I said, it is a 90% open road with 10% heavy city traffic conditions.

My oil mix this time is 4 qts Mobil 1 10-30, 1 1/2 qts Chevron dino 10-30, and 1 qt Chevron dino 30w. Delco PF454 filter.

With all the info above, what would you suggest for an OCI?
Thanks to all of you for making my addiction worse! Vern.
Vern, chill out, quit mixing and just get some Delvac.
Haley10, I put on about 50-75k/year on my trucks. Delvac is in my future. Under my conditions how long of an OCI would you go on Delvac? How long on my current brew? Chill out? I get the shakes if I don't mix!
This seams to be a great candidate for a 5W40 or 15W40 fleet oil (Delvac 1, Amsoil). How about the oil life monitor or 10,000 miles? I would do a few UOA's to see how it holds up after 10,000 though.
When it comes to big-block gas engines, I'm a big fan of using 40-weights, so you have many choices:

Mobil1 0w-40
Shell Rotella 5w-40
Mobil Truck & SUV 5w-40
Mobil Delvac 1 5w-40
Delo, Delvac, or Long-Life 15w-40
Amsoil 5w-40 or 15w-40
etc, etc, etc...

For any of these lubes, I'd suggest starting out with the "normal" OCI recommended by GM.

I can't honestly suggest an OCI for the mix you're currently using as I have no idea how it will perform. Wouldn't push it too far though...I'd highly recommend a UOA if you want to find out what is going on.

[ July 20, 2004, 07:20 PM: Message edited by: Jelly ]
Don't forget your tranny.
It has that cute little red spin-on conveniently located to make it even easier to change than the engine one. Also a drain plug in the pan and a fully reusable pan gasket if you want to take a look inside.
With your temps and applicaion I'm thinking 15w40 HDEO is perfect(no mixing required, they blend this stuff for big rigs). Is there a warranty concern as to viscosity or OCI? I see its still under the 3 year/36K mark.
Use Schaeffer #700 15W-40. If you have warranty concerns, use #703 10W-30. Either of these Schaeffer oils will perform very well in that engine in all temperatures except the coldest of winter...then #701 5W-30. Your oil change interval will probably be at least 10,000miles, but stick with GMs recommendations during the warranty period. Use the oil life monitor. These oils will also help keep the engine clean and reduce wear at a very reasonable price. In any case, you'll get better service sticking with only ONE oil rather than mixing. You do not know if the additive packages in each oil work together or hinder the effects of each other. Stick with mixing your drinks and keep the oil straight.

I would use M1 and change it every 7500 miles. Do a UOA or two inbetween to see whats happening, or dont (i never do).

Half the people on this site are so wound up in oil that they start by changing there Dino at 3k, learn alot about synthetics, and start extending there drains (which is smart), then, they start to over-think oil, and become fanatics, factoring every little thing, and eventually start getting scared and changing there synthetic oil at 3k again.

I have had 5 different vehicles i have run M1 on. One of them currently has 419k miles on it, and it had its oil changed every 10k, with 1 filter per 10k. forget the what ifs with air filters and leaking fluids into the oil. I never had a problem.


Dont be scared to run your M1 in that truck to 7500 miles, or 10k if you please. You wont have a problem. I know some oil nuts that will disagree, in fact, one of them changes there oil every 1500 miles, and guess what, he has only 120k on the engine and its burning oil. Changing it way to early wont help your engine to last any long, it will only help to ease your fear that you are doing somthing bad. And this is by all means incorrect.

M1 cars i own:

4x4 toyota 1987, 419k miles, 10k OCI (1 filter per change)

1993 Chevy Lumina, 278k miles, 10-15k OCI (1 filter per change)

1994 Toyota Corolla 1.8L, 153k miles, 7500k OCI (1 filter per change)

2003 Chevy cavalier 2.2L Ecotec, 12k miles, 7500k OCI (1 filter per change)

Do not spend $5 a quart on a quality synthetic and change it at 3k or by what your manual says for peace of mind, because your just fooling yourself.

To many people on this site learn the longevity properties of synthetics, then run all sorts of bogus tests that REALLY DONT PROOVE that the oil is no longer doing a fine protection job, and in result, foolishly change there oil way to early.

Do any of your cars take a long time to reach their OCI? In other words, what if it's a full year (or maybe a few months more) before you reach 7,500 - 10K miles?

Edit: Looking at the age/mileages it looks like you put on a good number of miles per year...

Interested in hearing what you think about how oil and especially the filters will hold up over the course of a year or more...my biggest concerns are not oil failure, but dilution/contamination and failure of the oil filter media.

Well, i own a small business, and this is sort of the "fleet" of cars that we use, excluding the 2003 cavalier. The other 3 cars are used by myself (toyo pickup) for hauling and sales. And the two cars are used by our salesmen, who travel most of there shift around ny/nj area. Its a manufacturing business. Also, i live in NY, and work in NJ, and its a 2 1/2 hour drive to my factory. These cars are always running. Alot of it is stop and go in town/city driving as well as highway.
to further answer your question:

I would say, the pickup truck runs, currently, around 20k miles a year. I change the oil twice as you can see.

Perhaps changing the filter every 5k could give me piece of mind but at this point why, the toyota is so old. the first 150k miles or so this engine had a FRAM oil filter in in for 10k periods. Then, when i learned of how FRAM filters were constructed, this soon changed to AC DELCO. Oil filters dont play as big a role as people think in oil filtration, they basically will protect your engine from a major failure, but they cant clean that oil like new.

It is impossible to stop all engine wear with certein oil and filter, or changing out the oil way to early. All the UOA's people get to test oil integrity doesnt really hit me as hard as others. Ok so the oil is starting to collect chemicals and particles and now its getting high saturated, so? This doesnt mean change the oil out ASAP. The oil is still doing its job; keeping metal to metal contact lubed. Does my mobil 1 do a better job at 3k on the oil at protecting my engine then at 9k in its life. I am sure it does, but not to the point where my engine is going to drastically loose miles off its life. Thats what alot of people fail to understand. Ok, so the oils properties and chemicals are not the same as when it was just put in, or its a bit saturated with wear metals. Its supposed to be, and i feel perfectly comfortable running "dirty" oil, as it still does a fine job of lubrication.

In the early 80's my neighbor started using "mobil 1" and claimed it would last 25k miles or somthin "crazy" like that. I did not go for it. He had that car for a long time, and i believe it was a cutlass sierra or somthing along that line. Alot of fleets started to use this for there business, so my very first truck for my job, i bought brand new, the 1987 4x4 toyota, after a 3k drain, i started with the m1, and just to play it safe, changed it at 10k instead of 25k (which i still think is a good idea, 25k will be oil that has broken down and not doing any job at all) but 10k is perfectly fine. The oil filter, well im pretty much in the dark. Does it hold up in that can? Maybe. Is it mush in there? perhaps. I really doubt it though. Alot of car manuals "long trip" intervals are now 7500 miles, and thats not far off from 10k, so im sure the filter holds up just fine. My toyota with 419k is just starting to burn a little oil now, past the valve guides i think. Not to shabby at all. I def feel m1 had alot to do with this. 250k is a sucess story, 419k and counting is a legend.

Do whatever you feel is comfortable. But I for one am telling everyone that being over concerned is just going to cost you more money and is not going to do much more for your investment then you think.

I currently run m1 5w-30 in the 03 cavalier and the 94 corolla, and m1 10w-30 in the 93 chevy lumina and the 87 toyota 4x4.

All of them get an AC Delco oil filter.
Air filters, they ususally get a mix, whatever is cheapest including FRAM. All paper air filters i feel are the same, i dont care what filter has more pleets then the other or which 1 looks like it came outa the factory the nicest looking. lets be serious here.

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