M1 TDT, 4277 miles, 08 Duramax

[Fulton 1]

Only 4277 miles on this sample from my LMM, but it represents 1 year of use (I don't drive the truck that much). Oil was Mobil 1 5W40 TDT, oil filter was Napa 7202, air filter is Banks CAI. This is without DPF and EGR and mild (PPE +90) tune. Driving is about 50/50 city/highway on this sample. No towing, no extended idling (more than ~ 5 minutes). Fuel is Chevron B5.

Based on what I see here I'm thinking I could go beyond the 1-year interval without issue.

 

[Fulton 1]

I should mention that this sample was my first run of the TDT. I broke the truck in on 15W40 Delvac, but never did any sampling of that. As you may recall, the TDT was hard to come by there for a while...

 

[daman]

Nice run looks good,waisted oil tho run it out longer next time she looks broke in.

TDT is a fine oil

 

[Steve S]

You don't need syn for your engine unless you get into freezing weather or 3 year oil change intervals. She looks good.Especially with the low engine miles.

 

[bullwinkle]

+1-if you're going to change it that often, Delvac 1300 would be fine, & a WHOLE LOT CHEAPER!!

 

[Fulton 1]

My intention isn't to change it this often. This was just a reference point for me. Historically, on my non daily drivers, I usually don't go more than a year on any particular oil without doing a UOA. Based on what I see here I'm going to go longer next time - maybe 18 months - and see how it looks. Seems a little more difficult to me to judge proper interval when you just don't drive them that much.

The good thing is that when I do drive the truck I usually go for trips of 20+ miles so it gets a chance to get nice and warmed up.

 

[dnewton3]

Your TBN is still 8, and there's no wear to speak of at all. I'd say you're only about 25% of the way there. 18 months is way short of the capability of this oil.

I suggest you get a Fumoto valve to get easy oil samples, so that you don't have to dump the oil to check it.

Dumping this oil at this exposure duration is a HUGE waste. If you're uncomfortable with pushing oil out for really long periods, then just run dino oil and you'd still be OK for a couple years given your serivce factors (no heavy towing, long drives up to temps, etc).

Interesting that your truck is so new, and does not exhibit the classic Cu spikes so prominent in Dmax trucks.

 

[Jim Allen]

Yeah, Fulton, 18 months is pretty conservative based on this sample but I applaud your cautious methodology.

Some of us have been experimenting with long time intervals and found that, under most circumstances, the time element can be stretched out over couple of years quite easily. The main requirements are regular (not necessarily frequent) longish runs to get it good and hot and that hot run run maintained for a minimum of about 30 minutes (clock starts ticking at full warmup). Environmental and storage conditions can also play a part, e.g. the truck is parked outside in a swamp ( : < ).

I've gone two years on good 'ol mineral oil with a couple of vehicles. This fall, I will sample a three year run on nothing more than Rotella-T 15W40 in a 8300 hour tractor. I will change it for sure this year because it's reached it's hour limit.

For the benefit of those who might have missed it, we should probably hasten to repeat that this truck is WITHOUT DPF and EGR. If both those systems were operational, as with a stock LMM, the OP would have to be much more cautious with long intervals due to potential soot buildup and fuel dilution. Still, that's more a product of miles and regeneration cycles, not time, but it bears watching more closely IMO.

 

[stockrex]

I have the same oil in my dmax. For warranty reasons do we yearly oil changes?

 

[dnewton3]

I do annual oil changes for warranty purposes. After the warranty expires, I likely won't.

If you're concerned about warranty, then stick with annual changes. And if you're going to do annual changes, there is ZERO reason to be running this, or any, expensive synthetics when any brand name dino oil will do just as well for a LOT less money.

 

[Jim Allen]

Since he's disabled DPF and EGR 9EGR delete kit??), does he need to worry about warranty?

 

[dnewton3]

Well, yes. The modified (or missing) parts would not be covered, but all the other lubricated parts (crank, rods, bearings, turbo, etc) are still covered.

Removing part of the exhaust treatment system AFTER the engine (DPF) has zero affect on the lube system. As for the EGR, there really isn't much it does to the oil, except make it cleaner once removed. One could reasonbly argue that improves the lube system, at the detriment of the combustion process.

 

[addyguy]

If you wanted to REALLY push it, this oil would most likely last over 5 years at your current mileage accumulation.

In 18 months, it's essentially suffered NO degredation at all. In scenarios like this, an oil like TDT is almost a 'lifetime fill'.