Oil Change Intervals

I agree with HEAVYD oil is cheap when your talking about overhauling an engine that may cost you $10k or more.....

I catch slack all the time from guys i run with about my oil changing....I change mine 10-12k miles normally
closer to 10k miles its just a pet peave of mine ive always done it with my personal vehicles and when i bought
my rig i kept doing it....

 

My CAT looked like new when it had to come apart because of a leaky liner (my fault)... I've been doing 50K oil changes (Delvac) for 700,000 miles.

Now, with my fresh overhaul, I'm installing a bypass filter and will start using AMSOIL and switching to 100K changes.... it can be done safely and save you lots of $$$ IF you do oil samples on a regular basis.

 

Could the cause of the high iron level be that the oil hasnt been changed in awhile so that now when its running the pistons are wearing??? But after the oil has been changed everything will show normal?

Thats what happened to my truck. The first sample i got back showed high iron level. But the second one showed all was fine. In fact the lab thought i did some repairs, which i hadnt. My guess is the dealer never changed the oil like they said they did, and i was running with bad oil...hence the high iron wear.

 

I see you are in Wisconsin. What about trying 2 changes a year using synthetic. Your truck will like you in the winter.

 

Contaminate levels should be adjusted depending on the miles on the oil...

Someone more knowledgeable than me can tell us but I don't THINK a 6NZ has steel pistons... I believe they are aluminum maybe with steel skirts... they are not cast iron AFAIK.

 

I'm going to switch to the AMSOIL 5W40 oil... I had been thinking of using Delvac 10W30 all along but it is hard to find on a shelf around here. Even the delvac wholesaler would have to order it for me.

I used to buy my Delvac 15W40 for $8.00 per gallon from my former company... kinda made it hard to make the switch.

 

Cat in Eau Claire charges about 15 bucks to do this.

 

Thats fine if thats what you want to do. But...at 200 bux a change, (it's an easy round number) and 120,000 miles a year you spend about $2400 in oil changes per year. Thats .02 cents per mile for that cost.

Look at the numbers this way, based on that 10,000 miles per month (and oil change). The monthly totals for fuel are .543 cents per mile (based on 6mpg) and a truck payment of $1250 so thats .125 per mile and an oil change is .020. so that means to buy fuel, truck payment and oil change it costs you .688 cents per mile before you pay any other bills.

Now if you can up the mileage and squeeze more miles per change the numbers look like this...fuel economy goes up to 6.3 which means .513 cents per mile truck payment stays the same at .125 but oil changes are now at 18,000 miles for a per mile cost of .133. Now the total is .650 per mile for a savings of about $3000.00 per year. Thats the direct savings number.

The indirect number will also get better. Less fuel used means less engine wear. That translates to longer engine life. Less fuel also means longer tire life. That means less cost per mile. Those numbers will be easy to pin down. Other savings that may be there won't be easy to pinpoint.

In short changing the oil too early may be impossible to justify in business terms. You can't say that you saved X amount of money in repairs because you can't say you would have spent that for the repair in the first place. What you can say is that you do it for your peace of mind.

 

Have no problem with Amsoil, I use the DEO 5w40 in my Jeep Liberty Diesel. But you might be dollars ahead by using a local oil supplier for the truck oil. I get a 40% synthetic blend from my supplier (their own labeled brand) for $9 a gallon in a 55 drum delivered to the house for free. I put used oil in another 55 drum and they pick it up for free when they deliver the new oil.

Been using their oil for a couple of years, and latest sample showed good results on oil at just under 25,000 miles.... 8ppm iron, 1 ppm lead, and .1 soot. Yep, only a tenth of a point of soot. And the truck gets an average of mid 7 mpg, pump to pump calculated. This on a 2006 ISX in an International 9400i with 630,000 miles on it.

If you choose to go with the Amsoil, that's cool. It is a good oil. I would get the Preferred Customer pricing and pick up the oil at one of the warehouses yourself. That will save you considerable cost. Just in the event you didn't know, preferred pricing is roughly 30% cheaper than retail. The other option is to get a dealer to put you on a commercial account. Pricing is better yet. Still, picking up the oil yourself at the warehouse is a big money saver either way.

I have to side with Smalltruck on the oil change interval. It is really not objective to state that changing your oil more often helps the engine last longer. I did 30,000 mile oil changes using Kendall 15w40 on a '96 ISX and got to 1.4 million before getting out of it and it still hadn't been opened up except for overhead and only used a gallon of oil in about 8,000 miles and still got 7+ mpg. And oils today are even better than they were then! I admit, I dropped to 25,000 mile intervals on my ISX for a while. Now that the engine is cleaned up from whatever the previous owner was using, I will probably go further on the OCI's.

If changing the oil more frequently helps the engine then, logically, it should be assumed that changing your oil each and every trip would really make a big difference. We all know that is silly, but making blanket claims about 10,000 mile oil changes will make the engine last longer is similar to the 3,000 miles oil changes being pushed by quick lube places for cars. There is no evidence to support the claim. Changing frequently may make one feel more warm and fuzzy, but is not based on sound evidence. True, under the most adverse conditions, a short interval like that may be justified. Not on any standard OTR road used engine.

But then, I guess we must all live within our comfort level.

 

If you cut your idle time you can increase your oil change interval...regardles of the oil you are using.

I like AMSOIL because it's a true synthetic...many synthetics are made from synthesized dino base stocks... the USA is the only country in the world that allows these oils to be advertised and sold as synthetics... everywhere else they are just plain old oil... maybe it'm just a stickler for details but I like to know exactly what I'm pouring into the engine.

I've had great luck with Delvac and Pennzoil Long Life... less than good results with Rotella (poor sample results and more oil consumption)...