Availability of Rotella T6 5W-40 synthetic or substitute?


It's time for my annual oil change. Years ago, I switched from the Ford oil to Rotella T6 5W-40 when Ford changed the formulation for the Motorcraft oil. However, now I cannot get the Rotella either. None of the auto parts shops here have it in stock or can get it now.

I can buy Rotella T6 15W-40, though. Can I substitute it for the 5W? If not, what oil should I switch to to replace the Rotella?

Thanks!
David
 

Anderson

GT Owner
May 8, 2021
28
San Diego & FL
I use Redline synthetic 5w-50. More expensive but certainly worth it.
 

2112

Blue/white 06'
Mark II Lifetime
 
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2112

Blue/white 06'
Mark II Lifetime
I haven't used in my FGT but I would feel pretty confident in it's capabilities.
 

PeteK

GT Owner
Mark II Lifetime
Apr 18, 2014
2,268
Kalama, Free part of WA State
David, long time no hear. How are things in Corvallis? Had the Black Shadow out lately?

Re the oil: The original Motorcraft oil is 5W-50, as you know. The more important part of the viscosity spec is the high viscosity rating when warm, that is the "50". The "5W" is for easier cold starts in winter. From our discussions, I don't think you drive your car much in the winter. Understanding that, I recommend that you go for the 15W-50 viscosity grade. That gives up a little cold starting ease, but maintains the film strength of the 50 when at operating temperature.

But I question why you want to change from the recommended Motorcraft 5W-50? That's what I have stuck with because I do oil analysis on my engine, and based on that analysis, I have extended my changes to 10,000 miles, using that oil. The oil maintains it's viscosity, TBN, and average wear metals for at least that long. Maybe the Rotella works as well, but I don't have the data to back that up.
 
David, long time no hear. How are things in Corvallis? Had the Black Shadow out lately?

Re the oil: The original Motorcraft oil is 5W-50, as you know. The more important part of the viscosity spec is the high viscosity rating when warm, that is the "50". The "5W" is for easier cold starts in winter. From our discussions, I don't think you drive your car much in the winter. Understanding that, I recommend that you go for the 15W-50 viscosity grade. That gives up a little cold starting ease, but maintains the film strength of the 50 when at operating temperature.

But I question why you want to change from the recommended Motorcraft 5W-50? That's what I have stuck with because I do oil analysis on my engine, and based on that analysis, I have extended my changes to 10,000 miles, using that oil. The oil maintains it's viscosity, TBN, and average wear metals for at least that long. Maybe the Rotella works as well, but I don't have the data to back that up.
Hi Pete:

One of these days I'll have to make the trip to Kalama! Both the Shadow and the Rapide are running well, I drove the Rapide and sidecar more than 100 miles a couple of weeks ago and it is a workout for the shoulders, I can tell you.

Anyway, I switched from the Motorcraft when Ford reduced the zinc content in their formulation. The Rotella was used by lots of folks even before that. In any case, the Rotella has the anti-wear additives the Motorcraft used to have, so I've been using it.
 

Nafod

GT Owner
Mark IV Lifetime
I still find this in cases at Sam's club. They do sell out, but as infrequently as I visit Sam's, I'm able to still get it. I use it for my F-350.
I also have the mobil 1 5-50w oil I use for my 12 Boss that is mostly a track car.
I get the Mobil at Napa. They tend to have a nationwide sale on Mobil 1 in the month of June. My local store didn't stock that weight combo, but could order it. Normally took a week. About 40% off. Six bottles per case and I normally buy 10 cases. Haven't done this in a few years, so not really up to date on what will be available for the Mobil 1..
The Rotella , I bought another case last month.
 

2112

Blue/white 06'
Mark II Lifetime
^^^^

Got me thinking. Walmart may be better than Amazon.


^^That is a link to the Walmart site
 
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spartan

GT Owner
Mark II Lifetime
Feb 11, 2017
1,216
Bloomfield Hills MI
Walmart was better than Amazon and Napa. Just stocked up on 15W-50 Mobil One. Delivery at no charge.