30 wt Rotella vs 10-40 wt

Sorry if this has been asked already many times. For past 5 years I've been using Ford Lehman recommended straight 30wt oil (Rotella) in my two diesel engines. I am in Houston and rarely is temp below 30 degF. where I shop for oil I see a lot of 10-40 Rotella but no 30 wt. American Diesel says it's OK to use the multi-weight but straight 30wt is preferred because engines will maintain a more steady operating pressure. What do most veteran owners say about this?

Have you tried Walmart? Every Walmart around here carries the T-1 30 wt. Although I have noticed that some other products vary store to store

Incoming!
Perkins not lehmans. I use Rotella 10W30 because even in southwest FL, ambient temps get well below 60F in the winter at morning startup. 2- The engine manual recommends 10W30 in all ambient temps. 3- Its also what the gen uses so only one type of oil to carry.
If I had a block or oil pan heater, I might use straight 30.

I used to use the 15-40wt Rotella because I travelled a lot in near feezing temps. Switched back to 30Wt and havent really noticed a difference in starting.

Rotella 30Wt at most Walmarts...but often just a few left or in stock. So I just order a e pack on line or more if needed and pickup at store if home delivery isnt free.

They also carry it at Advance oil, even in 5 gal pails, but way more expensive than Walmart.

NAPA also sells it in 5 gallon buckets in the form of their Fleet Plus label which is rebranded Valvoline. I used the straight 40 in my Detroits with excellent results. Preferred it over Rotella because it had much lower sulfated ash content, which was a spec Detroit focused on, not sure what the implications are for Lehmans.

As you and others note above, 10W40 is way more available than straight 30W. Years ago mutigrade oils had significantly less lubricity than straight weight oils and that is why Lehman and others wrote their manuals that way.

Today there is little difference between the two in lubricity and I would go with the multi-grade.

David

I am running SAE 40 Rotella .because American diesel marinized it and they recommend it. but I don't see where 15w 40 would hurt anything .I would also stay with Rotella.

I use 10-40 Rotella in my Lehman because the previous owner did. I am also a fan of 10-40 for diesels and do not like to change oil grades unless there is a real reason to.
I don't see any variation in oil pressure that ADC mentioned.

10W-40 Diesel oil? Pretty rare, must mean 15W40.

On a Lehman, use either SAE 30 or SAE 15W40 diesel rated oil, what ever makes you happy. I don't think you will see any difference in the performance of the lube.

Rotella is what I use. Not that I think it is the best, but never had any lube problems and you can get it anywhere.

On my genset, I use Rotella 10W30. Not that easy to find but it only runs 180F oil temp and I don't want the parasitic losses with it running all night on some flavor of 40wt. And manual calls for 10W30.

My main gets 15W40, it runs around 200F oil temp. And that is what manual calls for.

Thanks

Thanks for the replies everyone!

The PO of my boat used 15-40 Rotella for 15 years so I continued using it. We have SP225 Lehmans. Bob Smith said they recommended 30 weight but 15-40 was fine.

djmarchand said:

As you and others note above, 10W40 is way more available than straight 30W. Years ago mutigrade oils had significantly less lubricity than straight weight oils and that is why Lehman and others wrote their manuals that way.

Today there is little difference between the two in lubricity and I would go with the multi-grade.

David

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I think you meant to say viscosity rather than lubricity. Straight grade oils and multi-grade oils, when reaching operating temp, are of equal viscosity assuming 30 v. Multi 30, or 40 v 40. Therefore, operating pressure will be no different whether using straight grdae or multigrade oil.

CatJack.
No I think he meant libricity.
We’ve argued in the past about this (not specifically Ski) and I’ve always contended that non-milti-vis oil had no viscosity improver and was thus a better lubricant. MVI was at one time very tiny rubber balls (so I’ve heard or read) and probably like a powder but I don’t know. Now it appears from Ski’s post that possibly they have an improved MVI. Almost none of us start our engines when it is cold as in near or sub freezing temps. So the need for the lower viscosity at startup is unnecessary .. not needed. My engine started smartly always in Akaska.
Also many think the oil gets to the bearings sooner w MVis but I don’t think so. No reason for MV IMO. But using it has no downside that’s worth even mildly talking about.

MV was designed for cars in places like Minnesota where it gets way cold as a starting aid. People now forget what it was for.

I was using the Straight Rotella 30 weight in my 120 Lehman. I change to the 10:40 and my oil consumption went from a quart of day to almost nothing I have no explanation for this but that's what happened ,verified over 21 day trip

motion30,
I use Dello 30W and check oil level very seldom.
Basically dosn’t use any.
Your variation must be caused by something else.

There is much confusion about oil level in the FL engines. Perhaps you over fill and the level goes down fast right after. ??

I have never had a problem finding Rotella 30w in the Houston area.

You find it mostly at marine and truck places.

10W-40 Diesel oil? Pretty rare, must mean 15W40.

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Yes

I noticed yesterday Costco had Delo 400 15/40 for $30 per 3 gallon box.

Stick with what the engine is used to.

You can also order it through amazon. My last three orders where delivered perfectly.

I go with 15-40 in my Perkins.
Schaeffer of course ; )

You might want to read my post here:

Trawler Forum - View Single Post - Transmission oil- can I use mulitgrade?

+1 on Amazon. Where we live it is about an hour drive to do big shopping so we do a lot of Amazon to save the driving.

I have NA Hino diesels, the engine manual specs sae 30. They have always used the Rotella T 30 almost 2000 hours and they burn clean and I can’t tell by looking at the dipstick that they burn or leak any oil.

Comodave said:

+1 on Amazon. Where we live it is about an hour drive to do big shopping so we do a lot of Amazon to save the driving.

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Dave,
Wadduhgootaggainnst driving?
I think it’s recreation.
Got a nice car though.
30W (Dello) is all I use too.

I actually have a nice car too. I have better things to do with my time.

Looking fwd to tomorrow.

Nomad Willy said:

Looking fwd to tomorrow.

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Hey Eric,
Just changed out my commercial name ‘Schaefferoil’ for our boat name, “Knot Salted”
It is still ME!
Still selling the best oil..[emoji106]