Went to go get oil & filter , was told that Mobil 1 has discontinued 10-40. Now they have European formula , high mileage formula , extended mileage formula , high performance formula , etc. but no 10-40. Looking for suggestions what to run in my '93 LT1 in the heat of Summer in The South.
Is Mobil 1 still good stuff or have they become just another oil?

 

I mean factory reccomends 5w-30. I would assume that or a 10w-30 is sufficient. No real need for the 40. But it is available in the high mileage blend still if you choose. Pretty much any name brand conventional or synthetic oil is more than good enough now... no real up or down. API ratings are pretty tough combined with all the new oem certs. Run whatever the owners manual reccomends as far as weight for your region imo.

 

Uhh, 5w30 like the manufacturer recommends?

There's plenty of good synthetic oils out there now. Mobil 1 is good. But Castrol, pennzoil Platinum, etc all are too.

 

uhh.. ok, just seeing this right now as I was planning to go to Mobil1 after im done with this break in oil. Engine builder specifically called for 10w-40. Was planning on the switch this weekend. Guess I got some homework to do.

 

Sorry for sounding like a dumb ***.The previous owner told me he ran 10-40 as per spec. After checking spec the recommendation is 5-30 or 10-30 in high temp. I still question changes in the Mobil 1 product line.

 

IF Mobil has actually eliminated 10w40 (I just saw some @ Walmart two days ago), then I'd say that they did it b/c of:
1. reduced demand (virtually no OEM's are calling for oil that heavy anymore)
2. Because they can meet the wear/durability/protection criteria with a lighter, more popular and more fuel efficient oil.

 

The heavier weight oils were generally recommended for engines with "large" bearing clearances, when engine builders couldn't maintain the much more accurate machining tolerances and surface finishes that are required for the lighter weight oils. Is your engine builder admitting that his quality of machining does not match the current tight tolerances and surface finishes of modern manufacturing methods?

 

I think it also has to do with no reason to offer it in 5 flavors. Using a high mileage, extended service, euro, etc oil isn't going to hurt anything vs just a basic version, so why offer it and dilute your product line?

 

I recommend Mobil1's High Mileage varieties. The HM 10w30 has really impressive specs for high-temp/high-shear viscosity and has the ACEA3 rating. For driving in warm weather, and especially if you're going to hammer on it (track or autocross, for example), it's great stuff at a good price. For winter driving, I went with High Mileage 5w30, which doesn't have quite the high-temp properties but is still very good and has better cold viscosity for startups in cold weather. If your car is known to burn a little oil in the chambers, the new ESP line from M1 is probably going to leave less residue and will still protect amazingly well. They offer it in a 0w40. The downside of ESP is that it's expensive and not that easy to find. Amazon often has the best deals.

 

As we all know, frequent oil changes are the most important part when it comes to oil quality. If you barely drive it, change it once a year regardless. I still like using Mobil 1 10-30W full synthetic purchased from Walmart.

 

And the best part is that Mobil 1 currently has a $10 rebate per 5 quart jug (limit 2). That brings the Walmart price down to about $12 per 5 qt jug after rebate. (look online at Mobil 1 web site for the rebate (can do mail in or online).

I have been using 5-30 in mine.

I am not an oil expert, but I thought the 5-30 and 10-30 both are a 30 weight at operating temperatures. The cold temperature ratings are what is different. The 5 weight may flow better for initial start up or when cold. I thought that would be an advantage in most cases.

I also have read a little bit that many of the high mileage formulas use an additive that helps keep old seals from dying from age. I don't know how effective that is or not. I am not aware of other benefits to the high mileage oils. Does anyone on the forum have more details?

Good luck

 

This is all true, as far as it goes. Just know that viscosity is only one of many variables that determines an oil's ability to prevent wear. If you look at the full data sheet, you'll see things high-temp/high-shear viscosity, flashpoint, and others, as well as various manufacturer ratings such as ACEA that certify an oil's ability to meet various rigorous performance standards. The High Mileage M1 formulas probably do have seal additives as you said. They also tend to have tougher wear additive packages so that they stay in grade better under severe temps and pressures, but are less good at eeking out the last 1mpg from a car. AFAIK, High Mileage varieties cost about the same as "regular" M1.

 

Their viscosity at temp is also usually about the highest allowed for that oil weight. As in it is usually a heavy 5 or 10w30. They also tend to have better additive packages in general because they aren't as aimed at meeting oem guidelines. The suv formula from what I remembered was extremely stout and then was watered down. Blackstone and other independent labs have a ton of datasheets from analysis of the clean oil. Pick what you want to run, you can probably find tons of data on it.

 

As do I. I've got a feeling a lot of these "specialty" flavors of Mobil 1 have more to do with marketing.
I'm sure there are some differences (if for no other reason than to CYA) and I'd probably run one of the special flavors if any of my vehicles met the requirements (high mileage, etc.) but I wouldn't pay more for them.

Not a Mobil 1 expert, but have been using since 1976 and a few things I've seen / experienced over the years.
1. I don't know that "fully synthetic" is fully synthetic? I think Castrol was sued by Mobil years ago as Castrol was labeling their oil as fully synthetic, but the base stocks were not. Mobil sued, the judge ruled for Castrol, so Mobil copied Castrol and started using base stocks that were not synthetic.
2. Folks don't remember, but back in 1976 if you bought Mobil 1, it had in big red letters across the bottom of the label 25,000 Miles Between Oil Changes. It's reported they dropped those claims so as not to butt heads with manufacturers, many of whom were still recommending 3,000 mile oil changes, if not less.
3. Mobil 1 must have good shear strength - I ran it in my 1986 Kawasaki Concours, and changed it every 10,000 miles.
The Japanese bikes use the same oil for both engine & transmission (unlike Harleys) & I'm told the transmission is much tougher on the oil then motors are, especially when it comes to shear strength.
I tried a number of motorcycle specific boutique oils (costing much more than Mobil 1) & on all of them at 5,000 miles or so you could feel the shifter getting a bit "notchy" - change the oil & the shifter smoothed out. With Mobil 1, I never felt a change in the shifter for the 10,000 miles I ran it.

FWIW, I just changed the transmission fluid on my 2011 C6's manual transmission - put Mobil 1 ATF in it but I don't think I can tell any difference between it & the OEM fluid that I assume was in there. I was hoping it would smooth out the shift to 2nd when cold.

I just bought 5 qts. & a Mobil 1 filter at Advance Auto for $35.99 with a rebate for a free R/C car - probably give it to some kid in the neighborhood.
Didn't realize they had VISA Gift Card rebates going on - guess I'll make another trip to Advance Auto tomorrow for 5 more qts. & Mobil 1 filter - limit of 2 VISA Gift Cards per household.

Here's a list of all current Mobil 1 rebates: https://www.mobil.com/en/lubricants/promotions

 

They mostly have to do with manufacturer testing requirements. Some of those apply to older cars like a C4, and some don't. For instance, nobody here likely cares about fuel economy. OTOH, while you'd think we don't care about the emissions equipment protection that M1's ESP line offers, it's ability to burn cleaner and leave less deposits could be useful for an engine that burns a little oil, while at the same time it has passed the most stringent wear tests any manufacturer has ever conceived (I think it's VW504). I switched to that from High Mileage specifically for that reason. At the same time, an oil like High Mileage 10w30 that stays at the thicker end of 30w when leaned on hard is also going to burn less because it won't seep past rings and valve guides as easily, but that's diametrically opposed to good fuel economy - that's an easy tradeoff for people like us.

I don't believe that's the case. The only one it might be true for is ESP (it's not clear to me what they did with this one). However, the only thing that really matters is the tested performance. The problem with most Castrol (the euro formula 5w40 was an exception) is that it simply didn't perform as well. They do have Groups that they put these into, but it's not required to be on the container label. M1 is Group IV, whereas that old "severely hydrocracked base stock" Castrol **** was Group III (maybe it still is?).

 

OP you might try Mobil 1 0w40 "European Car Formula." I hear it is a very good oil. This is not the same as the ESP (emissions system protection) variety of Mobil 1.

 

From my notes (back when I kept up with this stuff and it didn't get so complicated):
Mobil says Extended Life oil has 50% more ‘SuperSyn’ than regular Mobil 1.
Don't know where I got that, but it was from a Mobil source (probably their website) or I would not have put it in my notes.

Of course, 50% MORE SuperSyn almost sounds like we could be back to the "is it fully synthetic" question?

Another little Mobil 1 tale...
My sister in law had a Datsun B210 with over 150,000 miles on it when she totaled it.
The mechanic that bought it for salvage hunted my brother down to find out what kind of oil they ran in it as he said he'd never seen an engine with that many miles on it that clean internally.
Of course, this was back in the early years of Mobil 1 (for street use).

 

I just watched a Scotty Kilmer Youtube video that he put out today. One of his followers asked about Mobil 1. Scotty said that they must have changed their formula recently as a racer friend of his says his race car started running at a higher oil temp during competition. He switched to another synthetic and the race car started running the lower temps again. Might want to check it out.
The Mobil 1 discussion starts at 8:20

 

Lot of variables there. I wouldn't say that is a "strong case", for...anything.

 

I can't comment on their Extended Life variety because I don't know anything about it. If you stick with their regular formula or High Mileage, though, you are getting Group IV synthetic base stock. Again, in the end what matters is how it actually performs. The specs and manufacturer certifications will tell you what you need to know about that.