5w-40 vs. 15w-40 the real truth?

[Rob_Roy]

If you prefer 5w-40 and Ford recommends it, there is no reason not to use it in your application.

I suppose a motorhome is severe service compared to what a lot of pickups do, but I would be curious to see what the oil temperatures are. My gut feeling is that the oil has a pretty easy life compared to a lot of diesels in commercial or agricultural service. The radiator on your motorhome should stay clean, there is lots of airflow around the engine, and after pulling a hill it gets to coast down the other side. Compare this to a tractor or forage harvester that runs at maximum load for 8-10 hours per day with only the engine fan to provide cooling...and a radiator that gains dust & debris throughout the day.

 

[mbacfp]

Thanks Rob. I want to say the highest engine temp I have seen is 246-247 farenheit. I drive it pretty easy...not too hard on it. The engine definitely has an easier life than most 6.7s.

 

[Dak27]

Hi, mbacfp! Reading through this thread, pretty much every one of BITOG's heaviest hitters have chimed in with excellent info. I'm a novice here, and I really enjoy the weatlh of knowledge I can glean from this site.

Last Summer, I bought my first Class 8 semi truck after close to a decade as a Company Driver. The last Company I drove for had their 2010 and newer Cummins ISX and Detroit DD15 motors on 50,000 mile OCI's (they also did UOA's on every motor), and company-wide they used 15w40 Conventional oil. I looked into the heads on 3 different DD15's, each with better than 750,000 miles on them, and all were amazingly clean. Of course, your Ford diesel motor is a bit different and used in a different fashion, but I wouldn't have a problem running a 15w40 Conventional year round in California.

I read you're following your manufacturer's OCI guidelines (me too, here with my truck), if they recommend 5W40 year round, and 5000 mile oci's to keep your warranty intact, that's what I'd do too, but if your warranty also gives you the choice of 15w40 conventional at 5000 mile OCI's, that's what I'd personally do.

Thinking back, all the Companies I've driven for were nationwide, operated year round in all weather, and all of them used Conventional oil, all 15w40, which is typically a,"default" weight for the Bean Counters over the Maintenance Departments. One Company had an account with Shell Rotella, another with Chevron Delo, the last with Mobil Delvac. Talking with many diesel mechanics in the shops over the years, the only time they ever saw an oil related engine failure, it was due to Driver negligence; not checking the dipstick and running the engine dry, go figure that one!, or a Driver running over debris in the lane of travel, taking out an oil line, and not noticing the engine lost oil pressure, until it was too late. Yep, it's always the Driver's fault. Lol, that's how the Trucking business works. But long story short, a crusty 35 year veteran diesel mechanic told me, keep an eye on your dipstick daily, top it off when it needs oil, and he hadn't seen a single engine go bad due to oil breakdown, etc in all his years turning wrenches.

There's certainly nothing "wrong" if you choose to stay with 5W40 Synthetic year round, but I think you could save money using a Conventional at your current OCI's, and your engine wouldn't "know" any different.

Take care! Dak

 

[JR]

Gokhan, it is overlooked or never stated around here that the full M1 line to my knowledge is CF-rated, not just 0w-40 and 5w-40, but the complete line up.

Before mobil went to the new label Mobil super,clean?, it was cf-rated also. I ran it in ywo VW 1.6's, 5w-20winter(yes brave).



harvey

 

[Shannow]

CF is not licencable any more, so they've changed to something like "meets the requirements of"...

I doubt that there's much out there that couldn't meet CF.

 

[Garak]

And CF was never a very robust specification to begin with, particularly if someone had chosen to fill their diesel engines with a CF PCMO, rather than an actual HDEO.

 

[supercity]

Originally Posted By: JR
it is overlooked or never stated around here that the full M1 line to my knowledge is CF-rated, not just 0w-40 and 5w-40, but the complete line up.(yes brave).


It is often overlooked or never stated that M1 0w40 and others meet A3/B4 and 229.5 which makes it a great light duty diesel oil. CF in comparison is redundant.

 

[mbacfp]

Thanks Dak.

Great info from all...much appreciated. I agree with you but will continue to follow Ford for warranty purposes. Thanks for the real word experiences.

 

[Garak]

Originally Posted By: supercity
It is often overlooked or never stated that M1 0w40 and others meet A3/B4 and 229.5 which makes it a great light duty diesel oil. CF in comparison is redundant.

The thing is, though, in North America, someone driving an older diesel truck or car will find that it calls for something like CF, rather than A3/B3 A3/B4. Those who don't understand the ACEA specs will have no idea that M1 0w-40 is a far superior lubricant to any basic CF lubricant they might have used back when the vehicle was new.

 

[Dak27]

Absolutely understood, regarding keeping your warranty intact . I think staying with a 5W40 Synthetic is your best bet. As we're getting into the coldest months of Winter, I've been thinking about switching to a semi-synthetic 10w30. The price difference isn't terribly bad, considering my motor holds 10 gallons. I would love to be able to afford using a synthetic 5W40 for easier cold startups in the Winter. I'm hoping to be able to at least try it once when I can afford to.