Canadian mechanic suggests shorter OCI’s for 6.7 Cummins

[Redhawk454]

Article is three years old but this stuck out to me:

Straight out of the gate we recommend 6000 km (3700 mile) oil changes if you are running conventional oil 15W/40. This should be a safe interval for city driving, stop and go driving, and idling. Some vehicles can get away with a 8000 km (5000 miles) stretch if you are mostly doing highway driving, consistently long trips where the engine can get nice and warm and run for extended periods.


running past these distances can really put your engine at risk of damage from a buildup of sludge and soot. For the skeptic that reads this article and drives by his oil change reminder message that pops up in the dash, an important point to know is that the message is triggered by restriction across the filter and / or engine run time, it doesn’t actually monitor oil degradation. The older Cummins powered trucks ran cool, clean intake air and the recommended oil change was 6000 kms (3700 miles). A 6.7 engine doesn’t filter any better, doesn’t hold any more oil, burns more fuel, plus it runs way hotter and dirtier internally, yet the manufacturer has increased the oil change interval recommendation. To us that doesn’t make sense and is evidenced by catastrophic engine failures we have seen in our shop.

Not sure what to think, the norm on these engines seems to be 10k miles

Cummins Diesel 6.7L Engine Oil Change Interval [Avoid Costly Repairs] - XL Mechanical Service Ltd.

The Cummins Diesel 6.7L is a great engine but there are things to really consider regarding oil change intervals. The important point to consider is that not all drivers are created equally. Do you just make short trips? Are you making consistently long hauls? Are you running conventional 15W/40...

xlmechanicalservice.ca

 

[skyactiv]

He's entitled to his opinion as are you and I. I don't agree with him.

 

[Redhawk454]

I think the idea of newer diesels being more filthy on the inside while suggesting to double the oil change interval is something I don’t understand.

 

[andyd]

I haven't got a dog in this discussion. But other than perhaps wasting oil, short OCIs are great for any IC engine.

 

[wwillson]

The article is a very low information article that is more like click bait.

 

[Redhawk454]

I read it more like a blog.

 

[Redhawk454]

His statement of

A 6.7 engine doesn’t filter any better, doesn’t hold any more oil, burns more fuel, plus it runs way hotter and dirtier internally, yet the manufacturer has increased the oil change interval recommendation.

has me wondering about the increase and increase and increase in oil change intervals by Cummins.

Did the oil rly improve that much? I’ve known for long that these newer diesels are dirtier internally yet the oil Change interval is 15k miles.

I found it by searching for 6.7 Cummins oil
Sludge buildup.

 

[Boomer]

Why do stiction additives sell so well??

 

[wwillson]

Why do stiction additives sell so well??

For which engine?

 

[tnt_motorsports]

I run 8k in my Cummins and according to Blackstone I can do 10k without any problem. I run semi synthetic oil in my Ram that’s 15w40. These engines hold 3 gallons of oil so not a small sump by any means.

It seems that all vehicles have increased OCI. My wife’s T&C goes roughly 9k before the EVIC comes on. The days of the 3,000 mile oil change are a thing of the past IMO.

Just my $0.02

 

[OLEJOE]

I run 8k in my Cummins and according to Blackstone I can do 10k without any problem. I run semi synthetic oil in my Ram that’s 15w40. These engines hold 3 gallons of oil so not a small sump by any means.

It seems that all vehicles have increased OCI. My wife’s T&C goes roughly 9k before the EVIC comes on. The days of the 3,000 mile oil change are a thing of the past IMO.

Just my $0.02

I plan to do 7500 miles on mine with R T6 5-40 and Stratapore filters.

 

[BrianF]

I ran and still run 10w30 semi synthetic out to 24,000km in the prairies and my old used oil analysis showed no real issues. I'll continue to do so.

 

[JWC86]

I think the idea of newer diesels being more filthy on the inside while suggesting to double the oil change interval is something I don’t understand.

I’m guessing (and I stress “guess”) is he’s referring to the EGR for running dirtier and perhaps DPF as to running warmer?

 

[Redhawk454]

I’m guessing (and I stress “guess”) is he’s referring to the EGR for running dirtier and perhaps DPF as to running warmer?

Yes, and I’m also confused as to why the oil change interval increased by 2.

They were 7,500 mile OCI’s and then in a model year they switched it to 15,000 mile OCI’s.

 

[JWC86]

Yes, and I’m also confused as to why the oil change interval increased by 2.

They were 7,500 mile OCI’s and then in a model year they switched it to 15,000 mile OCI’s.

Speculation here but I think its a push from marketing combined with them now caring less about how long the motor last, as long as it makes it though the warranty period.

 

[wwillson]

Yes, and I’m also confused as to why the oil change interval increased by 2.

They were 7,500 mile OCI’s and then in a model year they switched it to 15,000 mile OCI’s.

Did Cummins increase the capacity of the oil cooler and/or the oil pump? They did both in the Duramax with the L5P(2017) and L5Pv2 (2020).

 

[Redhawk454]

Speculation here but I think its a push from marketing combined with them now caring less about how long the motor last, as long as it makes it though the warranty period.

that Japanese Nissan gtr engineer with an interpreter said if you want a motor to last 500k miles change the oil every 3k miles..

I don’t look at my 6.7 Cummins from an accounting standpoint where I trade it in when it’s completely depreciated..

I want it to last a million miles!

 

[Redhawk454]

Did Cummins increase the capacity of the oil cooler and/or the oil pump? They did both in the Duramax with the L5P(2017) and L5Pv2 (2020).

I don’t know. Personally I don’t like the idea of 10k+ mile OCI’s on a turbocharged engine.

I know there are diesel mechanics on here, I’m not trying to suggest they don’t know what they’re talking about but I’m trying to find out what the truth is.

 

[tnt_motorsports]

Yes, and I’m also confused as to why the oil change interval increased by 2.

They were 7,500 mile OCI’s and then in a model year they switched it to 15,000 mile OCI’s.

they switched the OCI in 2013 when they went to FT4 with DEF. This cut down significantly on the amount of EGR in the engine.

Just my $0.02

 

[Number_35]

These engines sound like good candidates for bypass filters (if they're not already running them).

For what it's worth, when we lived in New Zealand for a year, there were a lot of diesel vehicles on the road there, mostly ex-JDM. The standard recommended OCIs were 5000 km for diesel and 10,000 km for petrol engines.