Group III vs Group IV (PAO) Basestocks in the TDI Engine

Re: Group III vs Group IV (PAO) Basestocks in the

[ QUOTE ]
dieseldorf said:
STBill, is the "15W40 argument" only a "wear vs no wear issue"?

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A good 15w40 like Delvac 1300 Super, other than having better wear protection than Delvac 1, will also cost 4 - 6 times less money and generally be available in more places.
Add to that, it's also has potential for extended drain intervals, formulated for high top ring issues and generally has specifications almost identical to Delvac 1.

So if your climate permits it, why not have your cake and eat it too!

Steve

Re: Group III vs Group IV (PAO) Basestocks in the

Link to current VAG compliant-oils

why can't I find a single 15W40 oil on the approved list /images/graemlins/confused.gif

Re: Group III vs Group IV (PAO) Basestocks in the

Dieseldorf,

From some of these comments, it's clear folks have not actually read this paper, or at least not understood what they were reading ....

There were four oils tested ... 5w-30 and 5w-40 group III formulations and 0w-30 and 0w-40 PAO based formulations. The 5w-30 and 0w-30 both had approx 0.6% VI modifier and the 5w-40 and 0w-40 had about 0.9% VI modifier. All these were ACEA "B3" type additive chemistries, rather than CI-4, HD diesel oils (this could make a difference).

The key findings are that the PAO based oils outperformed the Group III's and the two formulations with lower levels of VI modifier outperformed those with higher levels of polymer.

So my original comments still hold ...if you are using a low viscosity, 0w-30/5w-30/0w-40/5w-40 oil in the TDI, you'll get less ring sticking with a PAO based product - all things being equal. You are also better off with a 5w-30/10w-30 over a 0w-30 and a 5w-40/10w-40/15w-40 over a 0w-40. The idea is to minimize the # of VI modifier (or eliminate it entirely) in the formulation, which contributes to ring sticking.

The reference oil used was a 15w-40, ACEA "B3' quality, Group II petroleum oil. It actually performed significantly better than the 5w-40, Group III, light duty diesel oil, at least with regards to piston deposits. TxBill is 100% correct in that regard ....

Re: Group III vs Group IV (PAO) Basestocks in the

Ted, perhaps you will tell us why there are NO 15W 40 on the TDI's list of approved oils.

Re: Group III vs Group IV (PAO) Basestocks in the

yeah.. why run 15w-40 when you can run 0-40???

well.. the tests... thats why..

the test run on vw engines...

the test run on north american tdi engines..

the one where they could see NO measureable wear on the engines running 15w-40.. so they threw it out..

HOWEVER!!!!! the tests did show wear on the 5w-40, 0-40.. and the additives became very very very very critical..

but that is not enough to some...

you ask what is more important than wear???

well cold starting?? yeah.. i havent had a cold starting problem since '85 when they went full throttle bodys and cpu controled.. actually i hadnt had a cold starting problem on any model after about 75... seems they got the auto-chokes down pretty well and the glow plugs down ok..

so when was the last time it didnt start.. for your climate.. maybe you need something..but i'd try dual batteries before i changed oil..

next argument... whats more important than wear????

economy???

yes... show me.. do the tests... compare the costs...of increased oil price vrs price of fuel...

then factor in the wear...

whats the answer...

nobodys bothered to run repeatable tests.., just hype all the marketing hype on fabulous base oil that according to these tests on vw engines... well it sucks.. only the additives are making it work.. and even then the extreame problem of keeping the additives soluble seems to the the downfall of group IV oils.. so the answer...

he he he... if you dont wanna run a 15w-40.. then to save your engine... the oil manufactors have realized.. the inevitable..

you run a mixture of group III oils in the group iv base to keep the additives soluable and availible to the engine.. and still dillute the heavier groupIII bases with a group IV base for cold flow characteristics...

that points right back to the chevron oil study done saying exactly the same thing.. except it was done two year ago...

if you want the best wear.. 15w-40..

if you need a colder flow oil and still good wear.. a mix of group iii and group iv..

the group iv oils no longer pass the newer test standards... till the group iii is added..

while the group iii bases still pass with formulas from 1998....

whats more important than wear???
keeping soot in suspention relates directly to wear..
adding egr relates to wear..
adding turbo chargers and higher temps relate to wear..
extended changes adds to wear...

least ways the industry has pretty much moved to the right solution.. a near group III for 15w-40.. see the chevron study as to why its not necessary to go to full group III..

and if you need the extreame starting help.. get a new battery.. or/and run the 5w-40s now out there.. a mix of group iii base with a dillution of group iv to thin it a bit... but not too much or the wear goes up.. as shown due to additive instability and insoulbilty...

Re: Group III vs Group IV (PAO) Basestocks in the

[ QUOTE ]
dieseldorf said:
why can't I find a single 15W40 oil on the approved list /images/graemlins/confused.gif

[/ QUOTE ]

Don't understand why you're confused, the list you are posting is ONLY for 100hp PD engine.

Did you miss that or did you buy a PD?

Steve

Re: Group III vs Group IV (PAO) Basestocks in the

DD,

The list you have is for VW 505.01 rated oils for the Pumpe Duese engine - you'll notice that Mobil 1, 0w-40 and Delvac 1 aren't on this list either? FWIW, there are lots of 15w-40, VW 505.00 rated oils over in Europe - the spec has been around since about 1990. I also don't think a CI-4 rated, 15w-40 would have any problem passing the ACEA "B4" tests for a TDI diesel. There are so few passenger car diesels in the US that nobody bothers running these tests on commercial engine oils. The other factor is that VW is concerned with maximizing fuel efficiency, so they are now recommending 0w-30/5w-30/5w-40 for their gas/diesel engines. I wouldn't use a 15w-40 in extremely cold weather (say below 10F), but other than that I don't see any issues.

Specifically with regards to TDI piston deposits, I actually think a 15w-40, CI-4 rated, Group II petroleum oil would outperform a 5w-40, Group III, light duty diesel oil. The heavier, more stable base oil and the higher (12-13 TBN) detergency are the keys to minimizing piston deposits.

Re: Group III vs Group IV (PAO) Basestocks in the

[ QUOTE ]
canbluegolf said:
Did you miss that or did you buy a PD?

Steve

[/ QUOTE ]

steve, no. The 505.01 oil recommendations are not of immediate conern. The 505.00 spec is. Please have another look at the sheet. It covers: 500.00 AND 505.00 AND 505.01. There is also an additional sheet covering the LongLife oils which are all 0W 30 which was not posted.

Thanks.

Re: Group III vs Group IV (PAO) Basestocks in the

[ QUOTE ]
TooSlick said:

There are so few passenger car diesels in the US that nobody bothers running these tests on commercial engine oils.

Specifically with regards to TDI piston deposits, I actually think a 15w-40, CI-4 rated, Group II petroleum oil would outperform a 5w-40, Group III, light duty diesel oil. The heavier, more stable base oil and the higher (12-13 TBN) detergency are the keys to minimizing piston deposits.

[/ QUOTE ]

Ted, at some point I loose interest in how we get from Pt A to Pt B. My concern is the final result. That's what matters. Do I worry about spending $7 or $25 for a gallon of oil? I don't. It does concern me that there are documented oil analyses showing up more frequently with very high wear metals. Zanzabar's analysis (earlier this week) is yet another text book example of the concern I have: upper ring sticking. I am concerned about this because I suspect our 1996 Passat may partially exhibit this condition and is documented in oil analyses. The car did run Gr II (diesel-rated) oil from for the first 60,000 miles of its life since "synthetic oil" was not readily available when the car was sold nor did the mfr. recommend or suggest it. It all can be reduced to the lesser of evils and I don't really know which oil is best but I do know for sure I won't ever pour in a Gr II oil again so I believe that eliminates all 15W40 oils apart from AMSOIL's product and I don't need to run 15W40 at any time of the year.

[ QUOTE ]
TooSlick said:
Fowvay,

Amsoils 10w-40 now comes in @ 6.6% weight loss in the Noack test ...the data I have on Delvac 1 is for the older CH-4 stuff and was 10%. In fairness to Delvac 1, the CH-4 formulation had a pour point of -65F, so they were using a thinner (lower molecular weight) basestock.
Based on the technical data for the CI-4 rated Delvac 1, I would expect the Noack to be a bit lower, simply because they appear to be using a slightly thicker basestock. This is a general trend I have seen with most of the CI-4 formulations - I suspect these are being biased to improve the high temp properties for use in EGR equpped, commercial diesel engines. These next generation engines are going to run hotter and cause the oil to degrade faster.

TooSlick

[/ QUOTE ]

Ted, there was someone one here last week quoting that Delvac had a volatility of 13% per Exxon-Mobil specifications. I told him that is pathetic, even the old Shell Rotella 15W-40 dino II oil is as good as that, and that is NOT GOOD, its horrible.

[ QUOTE ]
Georgeseq said:


Synlube is also spelled Delvac 1. It is also called "real" synthetic vs. Group III wannabees..



George

[/ QUOTE ]

[ QUOTE ]
SkyPup said:
Ted, there was someone one here last week quoting that Delvac had a volatility of 13% per Exxon-Mobil specifications. I told him that is pathetic, even the old Shell Rotella 15W-40 dino II oil is as good as that, and that is NOT GOOD, its horrible.

[/ QUOTE ]

That would have been me /images/graemlins/smile.gif
Here's the reference for the Delvac
thinner verses thicker oil ~ what is best

13% is at the upper limit for the ACEA B# and E# tests.
15% is the upper limit for CI-4.

Steve

the 15w-40 oils are either group III or near group III. go to the api definition of group III and then check for instance the delo 400 15w-40... and it misses a the group III rating by 1 point.. the go to the sae study of why group II oils are only processed to the point that the ultra stable molecue is produced... then you will understand.. that farther processing to get the one point better does not produce better results.. farther processing to produce another 20 points does not improve performance.. so most 15w-40 diesel oils miss the group III designation by one or two points..

as to 15w-40... the vw engine tests run so the least wear on the 15w-40 rl90 reference oil.. the same oil that is mention in the acea tests that equal the 505 specs.. but then go to the acea e series tests.. the heavy duty tests.. were the 505 oils crap out.. the same rl-90 15w-40 passes with flying colors... again on a euro test that far exceeds the light duty vw 505 tests...
yes..i know your not in a heavy duty vehicle.. but the north american vw engine test pretty much puts the nail in the coffin... if you dont believe api ci-4.. if you dont believe the acea e series hd tests.. if you dont believe the acea b series and 505 tests...

yeah.. i know.. the salesmen who dont quote any tests...

yeah.. i know.. the million mile engines in canada and the us.. and now all over europe dont mean anything....

yeah.. the tests on real vw diesel engines dont mean squat..

now lets bring up volitility... ok... i dont add any oil between 10,000 mile changes... and i might be as low as 2 ounces.... before a change.. so what does that prove .. i mean driving in 110 degree heat.. with a real vw... where real world application,, real world heat... you mean there is more oil loss up north??? no pup.. that dog dont hunt...

my oil is always still in the cross-hatched area... so whatca gonna do now??? tell me that in 10,000 miles that the more expensive oil the wears more will only be a half ounce low??? gotta say also that when the engine is worn.. it will really eat the lighter bases anyway.. so much for volitility studies... even the ones that show the group III and /II oils are withing a per percentage points at 10k..... you know. the tests the your guoting above..

ok.. so whats next.. the smell.. the color.. what other price???

bottom line is.. does your car start????

after it starts.. how long does it take to rise above -30C??? the 15w-40 flows at about what -30c the 5w-40 flows at -35c... did that 5 degree make a diff??? the studies show actually the opposite in the wear test done in canada..


oops i forgot.. you guys dont believe documented and repeatable tests.. just bs and marketing hype and wives tales.... guess you are still running slick 50..

so.. does your car start??
dou you use more than a quart between changes??
(if your wear is that bad, qroup iv will probably make it worse)
and if you missed the pics.. of the engine pics at 300,000 miles where i replaced a leaking valve cover gasket.. you know better than to play the gunk card.. all the casting marks and numbers were crystal clear.. and the valve springs still had the bright red paint on them.. all the hardness marks on the headbolts were clearly clean and legible..

gas engines are lasting 200k every day now.. answer..
ALL the non sythetic oil is improved.. the engines are spotless if your running any higher quality oil.. and these oils are still lower than the oils we're talking about..(sf) give or take.. and ci-4 15w-40 oils exceed all spark engine tests..

you may want to run a thinner oil..and thats fine.. but you will NOT run a better oil..

you can spend more money.. but NOT get less wear..

you might get better mpg.. but i've yet to see anyone document that yet.. but that day is getting closer..

i pay 6.27 a gallon for a great 15w-40...

how much diesel fuel can i buy for the diff in price??
how much diesel fuel can i save??

somebody do a blind test.. a repeatable blind test..

then tell me the answer.. then factor in the cost of wear...

would be interesting....

Re: Group III vs Group IV (PAO) Basestocks in the

Hmmm.

At the risk of getting beheaded, I'm gonna throw into the ring here.

I think you two should invest in a couple of pairs of boxing gloves, and get this thing settled once and for all. The bottom line here is, most reputable oil manufacturers state in plain English that if you suffer an oil related problem from their product, bring them the receipts and they'll cover it. If they don't say that, and you choose to use their oil anyway, good for you. Now, as for whether group III or group XXIX or whatever is "best"...run what you are comfortable with. It's your flippin engine!! Ask around, do you homework, find out what YOU want to run in YOUR engine (cuz this thread has degraded beyond being helpful to those without a PhD in Quantum Fluid Phreakin Physics), and run it. My personal opinion is, if you use a good oil that's rated for turbo-diesel/EGR applications, and you use common sense (not trying to get 10k miles out of non-synthetic oil comes to mind), then you should be OK. You like Quaker State 30 weight, then run Quaker State 30 weight. Let us know how long it worked, and what happened if it didn't.

This whole one-upmanship crap belongs elsewhere.

Re: Group III vs Group IV (PAO) Basestocks in the

[ QUOTE ]
TooSlick said:
Specifically with regards to TDI piston deposits, I actually think a 15w-40, CI-4 rated, Group II petroleum oil would outperform a 5w-40, Group III, light duty diesel oil. The heavier, more stable base oil and the higher (12-13 TBN) detergency are the keys to minimizing piston deposits.

[/ QUOTE ]

How would you rate the performance of a Group II vs a Group IV for piston deposits?
Both oils rated CI-4/E5-02, with high TBN values, used in the proper climate.

Steve

Re: Group III vs Group IV (PAO) Basestocks in the

LWB I dont think this is personal, I think it's just a group of folks anal enough to debate oils down to the nitty gritty. Of course you're right, use what you want...but these people must beat themselves up over minute spec details. I am happy with my D1, and will use amsoil 15w40 in the cummins.. Not sure about their noack volatility, and do I give a F? Negative /images/graemlins/grin.gif

Re: Group III vs Group IV (PAO) Basestocks in the

The PAO/Ester blended basestocks are going to have the best resistance to heat and oxidation. So they will produce very low piston deposits and excellent engine cleanliness overall. Mobil released a technical paper several years back comparing Delvac 1 to Delvac 1300. the Delvac 1 did significantly better with regards to piston deposits in commercial diesel engines, even with significantly longer drain intervals. The paper can be downloaded from www.SAE.org for $10.00 US.

The point I was trying to make is that I don't think there is much difference between something like Delo 400, 15w-40, which is a group II petroleum oil, and Delo 400, 5w-40, which is a Group III "synthetic". Both oils use the same basic additive chemistry and I would expect the Group II and Group III basestocks to thermally decompose the same way. Aside from the cold weather benefit of the 5w-40, I think you'd see very similar oil analysis results from both of these. The Noack volatility of these two oils is very similar also, so I'd expect oil consumption to be about the same.

I see more of a gap between the PAO's and the Group III's than I do between the Group III and Group II stocks, FWIW.

Tooslick

Re: Group III vs Group IV (PAO) Basestocks in the

[ QUOTE ]
TooSlick said:
Mobil released a technical paper several years back comparing Delvac 1 to Delvac 1300. the Delvac 1 did significantly better with regards to piston deposits in commercial diesel engines, even with significantly longer drain intervals.

[/ QUOTE ]

I wonder how much both oils have improved since that paper, due to the higher standards they have to meet now. (CI-4 and such)

Steve

Re: Group III vs Group IV (PAO) Basestocks in the

OK, just to show I've been paying attention, I'll sum up.

If you drive like Grandma, live in the north, want to see 400,000 miles out of your engine, and don't like changing oil very much, use Amsoil Series 3000 5w-30.

If you drive like a madman, live in the south, want to see 1,000,000 miles out of your engine, and enjoy changing oil frequently, use any old good quality non-synthetic 15w-40.

Er, does that show I've been paying attention, or not paying attention? /images/graemlins/rolleyes.gif

Re: Group III vs Group IV (PAO) Basestocks in the

Sounds about right PaulB,

You may not have to increase the oil change frequency with the non-synthetic but, depending on the oil you choose, you'd probably want to back that up with an analysis at least once.

Steve

P.S. 15w40 non-synth is also good up north in the summer /images/graemlins/smile.gif

Re: Group III vs Group IV (PAO) Basestocks in the

[ QUOTE ]
TooSlick said:
I see more of a gap between the PAO's and the Group III's than I do between the Group III and Group II stocks, FWIW.

Tooslick

[/ QUOTE ]

I wonder how true this is. That is a question that I haven't really thought of.

How close is a Group II?

Re: Group III vs Group IV (PAO) Basestocks in the

I am trying to reconcile all of this information. Here is my theory. Please comment. Both the CI-4 Group III and the CI-4 Group IV oils have an additive package without VI modifiers. Both the CI-4 Group III and the CI-4 Group IV have high TBN, soot control, and detergency, and additives that include ones for wear and extreme pressure. There seems to be a balance to be struck between getting wear additives where they are wanted ("plate-out" boundary layer film) and yet retain detergency and soot control. These properties are at odds with each other. The scale may be tipped towards deposition in the case of the Group III but toward detergency in the Group IV. My take on it is that the lesser (slight perhaps) oxidative stability of the Group III tends to push the wear additives out of solution a bit by comparison, giving great wear characteristics but at the same time also tending to give ring deposits.

So where should the balance be? I don't know, it likely depends on the ring design & placement on the piston, amount of EGR, engine load, & fuel/air mix for starters. For TDIs I suspect that ring deposits may explain the high Fe and others. I suspect that Zanzabar's compression numbers don't tell the whole story since the compression test is at low RPM - in actual operation the ring loading is much higher plus there are stresses all over the place, acoustic "ring", etc. It is possible that a cylinder could be leaky in operation but show OK compression in a crank type test.

The argument on low temp. starting wear is weak for these oils. Bill's Canadian claim is believable. The issue at low temp. is drain on the battery. In a relatively short amount of time the oil will be at a temp. where it doesn't matter (if it starts). But, 5W40 better than a 15W40 in that aspect. Above about 10F, I agree with TS that it shouldn't make much difference to the battery.

Since we have at the least suspicions that ring deposits are an issue I am leaning toward Delvac 1. I don't doubt that other engine designs might be better suited to GIIIs (or "good" IIs even) if your not concerned about cold starts. My other incentive for Delvac 1 is that I travel a good bit up to the extreme Northeast and Quebec. Yeah, yeah I could get a heater but why bother (or take the cheap way out and start 'er up before bedtime, use a blanket, or set a lamp out under the hood... naah).

Question. Doesn't lowering the EGR, which is popular around here, tend to raise the piston ring temp. thus aggravating the ring deposition situation with oils other than Group IVs? It would also seem to be harder on the oil since the charge is more oxidizing w/o EGR, after all the EGR was added to lower NOx. Strange if it would be better for the oil from the standpoint of oxidative stability.

Re: Group III vs Group IV (PAO) Basestocks in the

Bear,

The oils I would specifically avoid are "wide range", light duty diesel oils made from Group III stocks. These would be 0w-40/5w-40/5w-50, oils that only have the VW 505 or ACEA "B3" rating (but not ACEA "B4") and a weaker additive package than CI-4 formulations. This would include products like Valvoline "Synpower" and Quaker State "European Formula", or the 5w-50 Castrol Syntec. This paper did not test CI-4 formulations made from group stocks, so I don't know how they would perform in the TDI. The extra detergency of the CI-4 formulations should be helpful in keeping the pistons clean.

The Group III stocks don't decompose as cleanly as PAO's and require more VI modifier to achieve the same SAE rating. The extra VI modifier tends to break down and cause varnish deposits that bind carbon particles in the upper ring groove. It looks as though most of the ACEA B4 oils sold in Europe contain at least some PAO basestock in order to help them pass the TDI tests for piston deposits and ring sticking.

Tooslick
www.lubedealer.com/Dixie_Synthetics

Re: Group III vs Group IV (PAO) Basestocks in the

ok.. the group iv dont hold additives real well. the group iii dont like cold weather.. All the BETTER oils are made from a combo of both.. meaning the now you get the best of both.. and that is why the wide range oils do very well.. actually some of the mixed oils outperform both bases even in the wide range oil now.. cant go by yesterdays rules.. even the group iv oils can no longer perform well on the test,, do to the problem with keep the additives in the mixture for long periods of time. this is why the group iv oils did worst in testing till new additives could be reformulated.. and finally mixing group iii oils into them solve the problems.. why the group iii oils passed with flying colors..

remember the new world wide tests useing real engines, not marketing hype... and oils have to pass in these various types of engines and testing...

so dont believe all the marketing hype you hear here.. go do some serious reading for yourself.

Re: Group III vs Group IV (PAO) Basestocks in the

TooSlick: Thanks for the comments. I think that you are right on the mark with regard to the VI modifiers and the breakdown of PAO vs. III. I suspect that the III has heteratoms plus probably has residual unsaturation due to benzene ring type compounds (that hydrotreat may not whack) and both of those can eventually lead to varnish. TS when you say PAO basestock (re: B4) in your last post you mean PAO/ester, right? I find it very interesting that an addition of a IV base may lower ring deposits.

SoTxBill: Good comments, thanks. I think that your argument about additive solubility is fine for PAO but I am not sure if it holds for PAO/ester. Same point in the end though. I would tend to think that the ester addition would create a new problem of additives being too soluble and not coming out at the right time, although I don't know for sure this is just my speculation. It seems that the motivation for blending III/IV could be along these lines, i.e. to make the additives "act right" solubility-wise. I think that the blends you mention are OK as long as there is no VI modifier.

I am changing my thinking about oil entirely. There is no right general answer to the question what oil is best. The answer depends on the situation. As an illustration suppose that large diesels have lower piston ring temp. due to their sheer size (ring placement, ability to get rid of heat?). I would say that a III, IV, or a blend of the 2 would be OK. From a wear standpoint, with no cold start worries, maybe the best order of preference would be III (including blends), IV as Bill suggests. Our TDIs are relatively small engines and might (I don't know) tend to have higher ring temps. or other characteristic (higher oxygen radical concentration from higher boost, less EGR, whatever) that enhances ring deposits. The scale then tips this way in order of preference: IV, III (III including blends).

I don't think we know if III, IV, or a III/IV blend will be best at this point. Some of us will be leary of any III in a TDI due to ring sticking.

Or is it pick your poison? I'll make up a number for the year 2033, location South Florida: 937,000 miles on my TDI running GIII and it goes due to piston ring sticking. The guy down the street gets 937,000 running IV, rings don't stick, but failure due to sheer wear. The girl next door has some of both problems running III/IV blend at 937,000.

I think that we are at a standstill here until we have some data to settle the III/IV issue. Until then......?

Re: Group III vs Group IV (PAO) Basestocks in the

Bill: Is there anything in particular that you want folks to read?

Hmm... maybe we can tell something from data around the club. Sticky rings would give elevated Fe and Cr? Cylinder wall wear would give elevated Fe?

Re: Group III vs Group IV (PAO) Basestocks in the

ok.. the group iv dont hold additives real well. the group iii dont like cold weather.. All the BETTER oils are made from a combo of both.. meaning the now you get the best of both..

Click to expand...

Bill

Have you ever looked at/considered using Schaeffer's S-7000 Synthetic Blend 15W-40? It has moly, as well.

Tim

Re: Group III vs Group IV (PAO) Basestocks in the

I have been using 15w-40 dino oil, and just switched to syn oil, mobil-1 5w-40 Diesel (suv & truck). it looks to have the same specs as the Delvac-1 5w-40, but it is much less money$$$$. I hate to use a 5w-40, and would prefer 15w-50 or 20w-50. I live in temps never below 33 Deg F but up to 110 Deg f. mostly 60F to 90 F, and need the thicker oil.
I can not find such a thing localy (say at Walmart) for low cost like this mobil-1 5w-40 Diesel (suv truck).
Does anyone know if this is the same as the Delvac-1 5w-40???? or is it a gimmick?

Thanks
John

Re: Group III vs Group IV (PAO) Basestocks in the

From what I read here the safest and the best bet in Ontario would be the Amsoil 10W-40 in the summer and the Amsoil s2000 0W-30 in the winter. Unfortunately the Delvac1 in not longer obtainable here.

And what is the story with the Castrol Syntec 5W-40? How come it's so unpopular and what's wrong with it? It's got all the VW 502/505 and the ACEA B4 rating.

Re: Group III vs Group IV (PAO) Basestocks in the

"And what is the story with the Castrol Syntec 5W-40? How come it's so unpopular and what's wrong with it? It's got all the VW 502/505 and the ACEA B4 rating."

the Castrol Syntec 5W-40 the dealer here has does not meet the spec for a TDI engine. it is 505 for year 1997 and earlier and is not -4 spec for the EGR TDI. 505 is not just 505, you must also go by the year too.