After noticing that Shell’s Rotella T Synthetic is $12.88 a gallon at Wal-Mart, I decided to do a little research on it and possibly give it a try. The MSDS shows that the primary base oil component is Shell’s XHVI--the same base oil used for Shell’s Helix Ultra. I know a lot of folks dismiss this base oil as a "synthetic pretender" because it’s not PAO. However, IMO of all the Group III base oils, XHVI is the only one that can legitimately claim to be "synthetic." Here is my reasoning behind that statement: Not all Group III base oils are created equal. XHVI does not begin as distilled crude. It is a wax isomerate, meaning that it is made from the slack wax removed from distilled crude in normal solvent dewaxing. This slack wax is catalytically transformed (isomerized) and hydrofinished into a chemically pure base oil which rivals PAO in virtually every category. PAO is made in much the same way, but the feedstock is ethylene gas rather than wax. Both processes involve the catalytic transformation of the feedstock molecules into a new state--namely, oil, and neither PAO or XHVI began as oil even though both use feedstocks that are derived from distilled crude.
It is true that Chevron and Petro-Canada produce Group III base oils that come close to PAO, but even though these oils are all hydroprocessed and utilize the same type of isomerization technology employed in the making of XHVI, they are not the same thing--they are produced from VGO just like Group II and Group II+ base oils. Only XHVI is made from pure petroleum slack wax and its CAS number is 92026-09-4. The CAS number for the more typical all-hydroprocessed Group II, II+, and III base oils is 64742-54-7.
Anyhow, once I saw that Rotella T Synthetic is made with Shell’s XHVI, I decided to give it a try in my Olds mini van. I’ve used Mobil 1 5w30 since its first oil change and the van now has over 147,000 miles on it. I change the oil and filter every 6000-7500 miles and the engine doesn’t use any oil between changes.
Since the day I bought it, the 3.4 engine in my van has had the infamous "tick" that virtually all GM 3.1 and 3.4 V6s have. This is caused by one or more pistons which have wrist pins that are at min spec and wrist pin openings that are at max spec. The tick usually goes away on most engines once they are fully warmed up and the piston and wrist pin have expanded to fill the extra clearance. The GM TSB on this problem says that this is not an engine durability issue, and given the service I've gotten out of mine, I'd say that is correct. When I changed the oil for the first time and went with Mobil 1 I noticed the tick was much less pronounced on start up and went away much quicker than with "regular" oil. This was confirmed in the two times when I took the van in for non-oil related service and received a "complimentary" oil change. I didn't even have to look at the ticket to know they'd done it; I could HEAR the difference as soon as I started the engine. Of course, I drove to the store, bought Mobil 1, and went home and changed it.
My 3.4 also suffers from the piston slap that these engines are prone to. It’s never been that pronounced, however, and goes away completely by the time the engine reaches normal operating temperature. This too has always been less noticeable with Mobil 1.
After switching to the Rotella Synthetic a month ago, the tick and piston slap are even LESS NOTICEABLE and go away much more quickly than with Mobil 1. Also, since this is a 5w40 oil, I was somewhat concerned that my gas mileage would be less, but in a trip up to DC last week the van got a little over 28 mpg, which is exactly what it always got running the Mobil 1.
Needless to say I am quite pleased with the Rotella Synthetic and when it’s time for the next oil change in my Chrysler, I’m probably going to switch it from Mobil 1 as well.
[ November 16, 2002, 07:49 PM: Message edited by: XHVI ]
Switched to Rotella Synthetic from Mobil 1
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I'm glad to hear you've found a product that works well for you, are you going to be doing oil analysis on it to see how it holds up in the long haul?
XHVI,
First of all welcome to the site. Always nice to see new people on here.
Shell finally updated their website on the Tech Specs for both the Rotella T and The Rotella Syn. The only thing I noticed is that Shell didn't get the CI rating on their Rotella Syn, but did get the SL. They did get the CI on the Rotella T however,
The Rotella Syn has sure become a great selling oil since Wal Mart lowered the price. One of the better oils on the market for the 5W40 range and the real beauty is it is OTC,
I did ask the Shell Tech Expert and he still likes the Rotella T for Diesel engine soot control. This was over 6 months ago. But many Ford Power Stroke, Dodge Cummins and VW TDI owners are giving the Shell Syn great reviews, along with many gas powered vehicle owners.
XHVI ![[Welcome!]](/forums/graemlins/welcome.gif)
Good post.
Very astute observations. Almost a call to differentiate group III!!!
I think Shell makes a good product line, and that's not just because they sponsor Ferrari!
Good post.
Very astute observations. Almost a call to differentiate group III!!!
I think Shell makes a good product line, and that's not just because they sponsor Ferrari!The oil has an almost negligble impact on gas mileage.
I used cheap dino 10W-40 in my Ford 4.6L SOHC V8 and got the same gas mileage as using 5W-30.
What you experienced wasn't because of the Shell 5W-40 formula.
I'd be worried about the weight spread. Unless its a real PAO its going to be loaded with Viscosity Improvers to reach that 35 weight spread.
quote:Not true. The viscosity index of the base oil determines how much viscosity improver will be needed in the finished product to cover a given spread. PAOs typically have viscosity indexes in the 135 to 165 range. Shell's XHVI has a viscosity index of >140. Therefore, a finished motor oil made with XHVI will require no more viscosity improver than a PAO based oil to cover the same spread.
Originally posted by metroplex: I'd be worried about the weight spread. Unless its a real PAO its going to be loaded with Viscosity Improvers to reach that 35 weight spread.
quote:Also, the Rotella T 5w-40 just barely slides under the bar of 5w. It's cold-cranking viscosity is 6400 cP @ -30*C. 6600 cP is the limit. I had never looked at Rotella T before, XHVI. It has nice specs and looks like a good bargain at $12.88/gal.
Originally posted by XHVI:quote:Not true. The viscosity index of the base oil determines how much viscosity improver will be needed in the finished product to cover a given spread. PAOs typically have viscosity indexes in the 135 to 165 range. Shell's XHVI has a viscosity index of >140. Therefore, a finished motor oil made with XHVI will require no more viscosity improver than a PAO based oil to cover the same spread.
Originally posted by metroplex: I'd be worried about the weight spread. Unless its a real PAO its going to be loaded with Viscosity Improvers to reach that 35 weight spread.
I was looking at the details of the Rotella Synth. I'm concerned about the 1.3% ash content in this Rotella T synthetic for use in a gasoline car engine?
What are the long term problems that using an oil with this high of an ash content might expect - if any?
quote:According to Shell, since the oil meets the SL spec and is not just for diesel engines, the additive package is designed to effectively handle gasoline engine deposits, whatever the source. The only potential problem to using this (or any) heavy duty fleet oil that is loaded with ZDDP (the EP additive) in a modern car engine is the issue of catalyst poisoning (which I think is a bunch of unproven baloney).
Originally posted by Cressida: I was looking at the details of the Rotella Synth. I'm concerned about the 1.3% ash content in this Rotella T synthetic for use in a gasoline car engine? What are the long term problems that using an oil with this high of an ash content might expect - if any?
The zinc causing damage to the cat is true, and there are two ways to cure it. One is to reduce the amount of zinc in the oil. The other way, which the oil companies did, is to reduce the volatility of the oil so the zinc stays in the oil and does not pass through the engine to the cat.
Ken
quote:Actually, they've done both.
Originally posted by Ken: The zinc causing damage to the cat is true, and there are two ways to cure it. One is to reduce the amount of zinc in the oil. The other way, which the oil companies did, is to reduce the volatility of the oil so the zinc stays in the oil and does not pass through the engine to the cat.
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quote:XHVI is a Group III base oil. Look at the MSDS for both Rotella Synthetic and Helix Ultra. The CAS# for XHVI is 92026-09-4 and is listed in the MSDS as "Hydrotreated Petroleum Slack Wax" at 65% to 74.99%. Some dillegent research on the Shell "global sollutions" web site revealed that slack wax is the feedstock for XHVI and Peter Van Benthuysen, a Shell engineer, has confirmed to me by e-mail that 92026-09-4 is indeed Shell's XHVI. XHVI is the primary compononet of both Rotella Synthetic and Helix Ultra, though Rotella Syn actually has MORE of it than Helix Ultra.
Originally posted by metroplex: I know its definitely a Group III because Shell even says so. I don't see anything about XHVI, just 3-9% HVI. From what i read it is NOT the same as the Helix Ultra from Europe.
quote:Yes, I am sure about that. The viscosity index of XHVI is >140. And it's not marketing hype because Shell doesn't really "market" this base oil. You really have to dig to find information on it. Also, keep in mind that Rotella T Synthetic is primarily a heavy duty diesel truck oil. Shear stability is of critical importance in such oils, especially when you consider they go for 30,000 mile drain intervals.
Originally posted by metroplex: Are you sure about that? To me it all sounds like a marketing gimmick - I'd have to see some results of Rotella T Synthetic 5W-40 after 3000-5000 miles.
metroplex
For what it's worth Shell Helix Ultra 5W40 is very ordinary on a Timken type machine and we have tested it several times. M1 OW40 TS eats it in this regard and even Pennzoils 10W30 Purebase was slightly better. I realise it isn't a true test but but we expected better for this top end prodsuct. Stil waiting on SS version of M1 0W40 to arrive to see how it performs.
Chiao..s
quote:Huh? I never said Rotella and Helix aren't "two different things." They are two completely different oils that happen to be based on Shell's XHVI. Why do you think Helix is "better"? What are your sources and criteria for determining which is better?
Originally posted by metroplex: Other sources confirm that Helix Ultra and the US Rotella T syn 5W-40 are two different things, both are good oils but the Helix Ultra is better.
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