IIRC, Valvoline Syntec is a Group III synthetic (PAO) also. Mobile 1 tri-synthetic is a Group IV (ester) base stock, with Group V (don't recall what Group V is) components in the addidive package.

Alex... paging Alex.

 

Chris, PAOs are not Group III. Group IIIs are superhydrotreated, isodewaxed oils. They are Group IIs that have been worked over. PAOs are Group IV, esters are Group V.

PAOs are built from small molecules. To make a "synthetic" petroleum product, crude oil is cracked into ethylene, a two carbon molecule that is the monomer unit for all hydrocarbons. Ethylene is then polymerized to molecules of (approximately) known composition. PAOs are larger molecules have a single unsaturation (double bond) at the head, and are typically made from 5 or more ethylene units. It would be very difficult to distill a pure cut of any PAO out of crude, it is way easier and cheaper to make them.

Many people have a mindset that synthetics cause leaks, and it is based in fact. When first introduced, Mobil1 caused a lot of leakage! The original Mobil1 formula was 100% PAO based with no ester. PAOs shrink seals, causing leakage. That is where esters come into play. Esters swell seals, and when a proper mix is achieved, the seals stay the same size. Mobil1 is now a blend of PAO and ester stocks.

PAO is very inert. It has good lubricating properties and holds additives well. The PAO based oil may have other swell additives added to reduce leakage. A 100% ester oil would be a bit scary to me, some PAO is better for oxidative stability. So, I would go for the PAO based oil, but go up a viscosity grade to 10W40.

 

Alex,

Could you name specific brands and models(so to speak) of GOOD synthetic oils to buy for oil changes on the Passat? PLEASE!!?!?!?!?! :bow:

 

Any synthetic oil is better then Dino. Any one. I use Mobil1 in other than recommended viscosity grades most of the time. My dealer uses Castrol, which is another really good one. The variability in the performance of synthetics is very small. The Valvoline 5W40 is the closest match to VW's specific oil recommendation.

A much more useful question is what is a good dino. For dino oils, the performance variance is HUGE!

 

Thanks!

Whats "dino"?

*Proceed with laughter*

 

As Alex pointed out, Valvoline Synpower 5w40 is the closest match out there to VW's specific oil requirements for the 1.8T. And I believe it is a true synthetic. From the website:

Is SynPower a full synthetic? Is SynPower motor oil PAO or ester based?
Yes, SynPower is 100% synthetic. Synpower uses a proprietary combination of various types of synthetic base oils to obtain optimum performance.

So it is a synthetic base stock, not dino base stock. Although the wording is kind of confusing, it doesn't say whether it is PAO based, ester based, or a mixture. But I'd guess it has some ester, because I have never leaked a single drop of oil in 30,000 miles with Synpower.

 

How about Royal Purple? I use Royal Purple 10W40 in my car. How does it compare to other synthetics?

 

I don't do boutique motor oils because the manufacturers are too cheap to do the engine tests and rely on iffy at best bench tests. Since my day job involves running such bench tests and interpreting their results, I am pretty confident in saying that a 4 ball weld has little to do with engine oil performance.

Royal Purple has esters in it. I don't know as much about it as I know about Amsoil, RedLine, and Pentosin, which are all decent based on their formulations, but should back up their mouths with some sequence data.

 

Alex, Is the Mobil 1 0w-40 good stuff, or is it too thin since 5w-40 is specified? It listed those VW specs on the back.

Thanks!

 

Thanks!

Whats "dino"?

*Proceed with laughter*

"Dino" as in "Dinosaur" oil is non-synthetic, "natural" oil -- oil from extraction and/or refinement.

Synths are formed via chemical reactions.

 

And how about that Shell Rotella T? Cheapest 5W-40 around (at Stuff Mart), but *aimed* at diesels (although SL rated...and recommended for gasoline motors).

Any reason NOT to use Shell Rotella T in a gasoline motor? (any *technical* reason?)

Results of search:

I had the same question a few months ago in regard to the Rotella T 5w-40 in our 1.8T engine. I went into Shell forum and discovered that there was some one that has a Passat 1.8T with CHIP ECU who had posted the same question to the Shell TechExpert. See below for the snip of the TechExpert reply (sorry for cut & paste, Shell site doesn't have the sub-link url feature).

May be other B5ers will chime in and clarify the Shell TechExpert statement below.

=============

TechExpert
Technical Expert

Reged: 01/22/02
Posts: 58

Re: Is Rotella synthetic right for me? [re: passataranamous]
08/29/02 05:34 AM Edit Reply

It sounds like you’re doing some interesting things with your engine. And looking for the best performing oil is critical with the increased performance you’re developing.

Shell has just introduced FormulaShell ® Synthetic, but only in SAE viscosity grades 5W-30 and 10W-30. Shell ROTELLA ® T Synthetic SAE 5W-40 would be ideal for your application if VW recommends API Service Category SL (or earlier, like SJ) oil performance only. The more robust performance of diesel engine oils (compared to passenger car only oils) can help protect your engine from excessive deposits and wear, especially with what you’ve done to increase power. But ROTELLA T Synthetic does not meet all API Certification Mark or ILSAC GF-3 (or earlier) requirements, which VW may also recommend for oil used in your engine.

============================


Q:
Mobil 1 with SuperSyn™ is an API CF oil and Mobil Delvac 1® is an API SH oil. Since I have both a gasoline and a diesel engine, which is better?

A:
Gasoline and diesel engine oils are formulated differently, but they do have some cross application. This is particularly useful for fleet operations that have a variety of engines. Being able to use one motor oil helps reduce inventory and eliminate misapplication mistakes. But we do not attempt to compare Mobil Delvac 1 to Mobil 1 with SuperSyn™, since they are primarily formulated for different applications.

For consumer use, we suggest that you should be guided by your primary application in deciding which synthetic motor oil to use. And keep in mind that some diesel engine oils now call for CE, CF-4, CG-4, CH-4 or CI-4 – which requires the use of Mobil Delvac 1 or Mobil Delvac® 1300 Super.

Whether you have a gasoline or a diesel engine, the owner's manual is the best place to look to determine what oil you should use – but you need to get two pieces of information:


The viscosity grade, and
The API service category (API SL, SJ, SH/CF, CD, etc.)

 

From what I've read, Rotella seems just fine.

 

Having read a lot of threads on oil, I am comparing the technical features of Castrol, Motul, Amsoil and Pennzoil, hoping I could pick the best for my 1.8t. Based on these values, which oil can be the best for a 1.8t engine? Which terminology matters the most? Also, is group IV necessarily better than III? If so which oil(s) below are group IV?



Motul and Mobil 1 have the highest flash point:230

Mobil 1 has the highest viscosity index: 185

Pennzoil has the lowest pour point: -45C

Motul has the highest viscosity at 100C: 14.2



http://www.motul.com/system/product...iptions/technical_data_sheets/52/original/8100_X-cess_5W-40_(GB).pdf?1357663396

http://www.pennzoil.com/wp-content/uploads/2012/02/PENNZOILULTRAFullSyntheticMotorOil.pdf

http://www.amsoil.com/lit/databulletins/g3079.pdf

Mobil 1™ 0W-40

 

What matters is the VW spec approval . If the oil meets that you're good to go . Mobil1 o-40 is selling for under $25 per 5 quart jug at Walmart and it meets the VW spec for my car .

 

Still, I have a feeling VW approved group IV oils are better than VW approved group IIIs.

 

Like arpad said, if it has VW 502.00 on the bottle, you are good to go. That's the only "terminology" that really matters. If it doesn't have that certification, use at your own risk.

The remaining subtle differences between oils are fun to debate (bobistheoilguy.com is the place to go for that), but are otherwise not particularly relevant to the longevity of your car.