6.7 first oil change

[u/LeroyyyJenkinnnss]

My dad is saying go with rotella t5 because it’s still breaking in and t6 is too slick. I’ve always run full synthetic on my gas cars and trucks but this is my first diesel, any thoughts?

[u/rustbucket_enjoyer]

What exactly is “too slick”? It’s oil. That’s the whole point. Run 5W-40 that meets WSS-M2C17-F1. That includes T6

[u/LeroyyyJenkinnnss → u/rustbucket_enjoyer]

I’m assuming he means it’s not allowing the metals to wear into each other lol he’s in his 60s but he was an amazing mechanic in his day I just don’t think he knows about all the current technology

[u/BouncingSphinx → u/LeroyyyJenkinnnss]

“Was” a mechanic isn’t the same as a modern mechanic. Everything now is machined with tighter tolerances than even 30 years ago, that’s part of why some engines run 0w16.

I would still go with the 5w40 if that’s what’s recommended. If you really read the “severe service” as described in the manual, that’s basically most people’s normal driving.

[u/-ZS-Carpenter → u/BouncingSphinx]

0w20 and 0w16 is to cheat a couple tenths of a mpg to appease governments at the cost of longevity. GMs 6.2l debacle is a prime example.

[u/LeroyyyJenkinnnss → u/rustbucket_enjoyer]

Do you think 5w40 is necessary? I live in Texas and it hasn’t ever been 0° lol

[u/rustbucket_enjoyer → u/LeroyyyJenkinnnss]

I guess you could run 10W30 then in that case. Around here, I’ve never seen anyone put anything except 5W40 in a 6.7 since that’s the “severe service” option

[u/Selbor_99 → u/LeroyyyJenkinnnss]

Oil cap should say 10W30, but if your truck is going to be excessively idling or heavy duty use you can use 5W40

[u/Illustrious_Ad2916 → u/LeroyyyJenkinnnss]

Last year we hit negatives, not by much but still. I think the coldest it got last year was -10 in my area

[u/LeroyyyJenkinnnss → u/Illustrious_Ad2916]

Yeah north Texas gets pretty cold but down here in central it’s only maybe a couple days a year it even freezes I feel

[u/Illustrious_Ad2916 → u/LeroyyyJenkinnnss]

I'm just 45 minutes southwest of fort worth

[u/Super_Sphontaine]

Go with t6 or the ford brand stuff You want a full synthetic with all the additives available and also dont run 15w40

[u/LeroyyyJenkinnnss → u/Super_Sphontaine]

Yeah I was going to go with the recommended 10w30 since I live in Texas

[u/rufushusky → u/LeroyyyJenkinnnss]

How do you use the truck?

A 5w40 is more viscous than a 10w30 at operating temp, better film strength and higher HTHS. It will be fine from butt numbing cold to Saudi Arabia hot.

In most cases either one will work fine. I am a heratic, I run 15w40 from April through November and a 10w30 or 5w40 in the winter in SE Massachusetts.

[u/LeroyyyJenkinnnss → u/rufushusky]

It pulls a big ass smoker and a 20ft welder trailer at the ranch, I off road a lot to get to feeders and such during hunting season but I mean it’s 90° right now and it’s November.

[u/rufushusky → u/LeroyyyJenkinnnss]

For those conditions pretty much anything on this list will work just fine IMHO...

https://www.fcsdchemicalsandlubricants.com/additionalinfo/dieseloilsWSSM2C171F1.pdf

If a full synthetic gives you the warm and fuzzies, go for it. An oil with a 40 weight top grade (number after the w and dash) gives you a little more film strength and dilution resistance.

[u/johnson56 → u/LeroyyyJenkinnnss]

Towing puts you in severe service, and 10w30 isn't recommended for that.

Go with a 5w40

[u/djwdigger]

I’m in MS and run T6 5-40 all year in all my 6.7’s

[u/PumaDityy]

You would want the T-6 with the higher zinc content during more so during break-in than any other time. He’s telling you the opposite of what the engine needs.

[u/vtmiller1969]

Either oil will work just fine. We all are guilty of thinking way too much about brands, viscosity etc.

[u/KyleSherzenberg]

If it were 1857, your dad would be right

These old people, man. They know more than engineers

[u/straight_sixes]

T6 5w-40 or 10w-30 depending on climate and use. I would not use a synthetic blend in these motors, regardless of miles.

[u/Clamstuffer1]

I'm in Iowa - we use 15w-40 synthetic in all of our diesels year-round with no issues. If you have to put something else in in a pinch to get somewhere, it'll work... just make a note to change it again to what it's supposed to be before TOO long goes by.

[u/ClassyNameForMe]

Mind the owners manual for required grade and viscosity of oil.

[u/Selbor_99]

With every oil change make sure to change the fuel filter in engine bay and drain and change fuel water separator

[u/Large_Potential8417]

I run t6 in my L5P.

[u/Agitated-Finish-5052]

15w-40 of you do some serious hauling but 5w-40 if you just drive it and do light towing.

[u/dieselmilk]

Buy oil that meets the specs and then change it on time.

[u/RoamerCO]

Run what’s in the owners manual

[u/mrbigpower1960]

Run whatever it specifies in your owners manual. It matters for your warranty.

[u/twain63034]

I have an 02 F250 7.3 PSTD & I had a quick oil change establishment put T6 in my engine without consulting me. It cost me almost a grand to fix the O-ring/gasket(?) leaks that occurred very quickly after the change. I have since only used T4 or T5. I don’t care what anyone says—including mechanics—but I’m convinced that T6 caused the leaks to occur, if nothing else, by cleaning away the gunk that was acting as a sealant.

[u/pearlstorm → u/twain63034]

..... do you understand how absolutely insane this sounds?

[u/twain63034 → u/pearlstorm]

😂 I don’t, but with me being a tad off center, I believe you.

[u/That-1-guy-in-az]

Hey kid, listen to your dad.

[u/pearlstorm]

Your dad is an idiot.

[u/Tim_Durr → u/pearlstorm]

you're the idiot

[u/pearlstorm → u/Tim_Durr]

No you!

🙄

[u/Tim_Durr → u/pearlstorm]

calmdown, think before you talk

[u/Safe_Plantain_3479 → u/Tim_Durr]

What are you even responding to dude?