What oil for my Fabia? My search for an answer

[Morris8]

Yes, I’m raising this old chestnut of engine oil again! However, as I’m now retired I have the time to indulge my passion for looking things up. So I thought I’d give you the benefit (?) of what I think I’ve found.

When the family purchased its 2010 htp 12v 70 b.h.p. Fabia a year ago, the choice of oil seemed simple. The handbook says either VW504 or VW502 specification for fixed interval servicing (1 year or 10,000 miles whichever comes first), and VW504 only for variable (extended servicing intervals). As I try to run my cars for as long as possible, I went for my usual 5000 miles (or 6 months) OCI . Ah, but then choices; do I run VW504 or 502, and what grade? 504 only comes in 5w30, 502 comes in a variety of grades. Remember, I’m trying to run my car for as long as possible; I’m not interested in a couple of extra miles per gallon fuel economy; I want my engine protected so it can last, and if I have to pay a few quid extra at each oil change I’ll happily do this (a lot cheaper than a new car or recon engine every few years).

My first port of call was the Lubrizol oil performance comparison website. This has a neat little tool that enables you the compare the performance of various oil specs. If you plug in the latest 502 and 504 specs there is no contest:  504 outperforms or equals  502 in every respect;  most important for me, 504 is much better for reducing engine wear.  So, choice made I thought; I can get 5 litres of vw504 spec. Quantum Longlife 3 on ebay for under £30, what’s not to like?

Well, my next check was various websites including Briskoda, Bobistheoilguy, Audiworld etc. The knowledge that some of the guys on these websites appear to have is mind boggling, so to a relative novice on oils like me, making sense of it is not an easy task. My conclusion trawling through pages and pages of this stuff is that there is indeed a lot of support for putting 504 in most VAG engines, but there are some quite persuasive detractors, to the point that some argue that 502 is actually better than 504 for some engines, and might hold up better even over 10,000 miles.

The first point to make is that, contrary to what one might think, 504 is not a simple advanced replacement for 502 (not like API SM superceding or replacing API  SL). This is why you do not find oils claiming to meet both 502 and 504 specs. For example, 504 cannot be used with high sulphur fuels whereas 502 can. This meant that up until recently, 504 was not recommended in parts of the the USA where low sulphur fuels were not readily available (this might also account for the fact that some older handbooks specify only 502 for fixed intervals). Also 502 has higher initial ‘TBN’; this stands for Total Base Number, which I understand indicates the ability of the oil to neutralise corrosive acids.  However, this in turn has led to debates about whether or not the TBN for 504, though starting lower, holds up better as the oil declines with age. In addition,  504 apparently has lower NOACK   evaporation loss, which apparently is good, as this means the oil is likely to evaporate and go thin on moving parts at high temperatures; so more protection. But then 502 is higher on zinc, which is supposedly good for engine protection but rubbish for catalytic converters (which is why 502 is allegedly much poorer on ‘after treatment compatibility’). And then there is some debate about the efficacy of other additives in 504 that compensate for the loss of zinc. And so it goes on.

What about grade? At present 504 only comes in 5w30; 502 comes in a variety of grades but 5w40 seems to be the most popular. The jury seems well and truly out on this one; I've read that  40 is thicker so reduces wear and reduces oil consumption, 30 is thinner so gets less hot and reduces wear and oil consumption, and the 30 and 40 specs for vw 502 and 504 are so close that it makes no difference.  etc.etc. I soon gave up on this one. 

Right, so there is a quite a movement in favour of 504, but with some often very vocal disagreement, and both claim to back their views up with technical arguments.  But then we come to another point. Let’s say, on paper, like on the Lubrizol chart, for even for fixed intervals, 504 is a clearly better choice overall (if you don’t mind paying extra), does it really make any difference in practice? Clearly, some experienced contributors to this and other websites appear to have run their VAG cars to very high mileages on 502 spec. oils with no problems. (Indeed, I ran my Mk2 Golfs to over 190,000 miles each on vw500/501 spec oils before one was written off, and the other traded in for a bigger car.) But might they have lasted even longer on 504? We don’t know. There is also an argument that the move to 504 might have contributed to some of the catastrophic engine failures that have plagued VAG over the last decade or so; but it’s not clear to me whether this is confounding the effects of 504 with variable extended service intervals. Is there any definitive evidence that  504 results in more engine failures on fixed intervals? Again, we don't know.

So what have I learned about whether you should put 502 or 504 in your petrol Fabia on fixed interval service schedules? If you want to save some money and especially if you don’t intend keeping the car for long, you’d probably do better putting 502 in it. On the other hand, if you don’t mind spending a bit more and intend hanging on the car, you might consider putting 504 in it, especially if you love your EGR valve and catalytic converter. But, as far as I can see, no-one really has a definitive answer, at least for now (as I said, there seem to be plenty of VAG motors around on very high mileages that have never seen a drop of 504 in their lives). For the moment, with the Lubrizol chart at the front of my mind, I’ve got Quantum vw504 spec in mine, fingers crossed! Good luck.

[Ootohere]

I believe if you cherish your car do not use Long Life oil if you have the choice.  Those with a TDI from VW do not have a choice.

Those with a petrol do. 

I have no idea where the idea that Long Life oil is superior.  Maybe a different formulations and ingredients.  Seems not to make a VW TSI any less likely to go pop.

 

*I would use VW502 for my petrol engines even if it cost more than VW504 5w 30 FS III*

 

So maybe if you care for your engine use  VW 502,  if you want for Fixed Services so 5w 40 FS. 

  If you want use VW504 for Fixed you can & it is what is needed for variable. so 5w 39 FS III  (Long Life.)

http://volkswagen.co.uk/owners/servicing/regimes

 

 

Its not rocket science really. 

 Any brand, no need for anything special or expensive.

 

http://briskoda.net/forums/topic/476936-fabia-htp-rattle-after-oil-change

 

Edited 4 February, 2020 by Roottootemblowinootsoot

[Morris8]

As far as I can see, the idea that Longlife is superior comes from data like the Lubrizol charts. But as you say, whether it makes any real difference in practice is another matter.

[Ootohere]

It does make a difference to some.  Long life oil and short lived engines.

Maybe just bad engines in the first place. Never heard of VW502 5w 30 FS being an issue or the possible reason for the early demise of a petrol VW engine.

 

Odd how the rattle subject often comes up where VW 504/507 is the oil being use with Petrol VW Group engines with DIY or Dealership / Independent servicing.

[Morris8]

Assuming the rattle woes are not just due to rubbish engines, I think the difficulty is deciding whether the problem is due to the oil or the service interval.  As I said originally, on paper the specs for 504 look pretty impressive, but having said this, for simple petrol engines I can also see merit in the idea of sticking to what seems to work in practice (i.e. fixed interval vw502); i.e. if it ain't broke don't fix it.  

[Breezy_Pete]

39 minutes ago, Morris8 said:

especially if you love your EGR valve

Struggling to see the relevance of the oil choice here?

Does your engine even have one? What code is your engine, BZG?

 

[Ootohere]

@Morris8

I did not think your car in 2010 had a code for Variable / Flexible servicing. I could be wrong though. 

You would need to look in the Service Book sticker or the Build Sticker in the Spare Tyre well.

[Morris8]

No, my cgpa engine does not have an EGR valve, but if one believes the Lubrizol charts and other sources, and your car does have an EGR valve, the principle should apply. Obviously my car has a cat. The reason I personally chose 504 was that I could get it cheaply and the specs looked superior. However, as I said, I'm genuinely ambivalent about this;  I'm absolutely not trying to promote Longlife oil, I'm just reporting what I found in my searches. 

[Morris8]

In my owners handbook (p. 230) for petrol engines on fixed service intervals (QG0 and QG2) it says, vw 501, 502, and 504; and 503 and 504 for flexible service intervals (QG1). The confusion about this, and different specs from  different sources, was exactly what promoted my original post.  

[Breezy_Pete]

Appreciate your efforts fella. 

If it's any encouragement, our 2005 vintage HTP is on about 172 thousand miles and has had no fundamental engine issues.  We bought it at just under 100k miles, and it has seen nothing but 502 00 ever since, roughly on the same time/mileage intervals as you're doing.

 

It did have a new EGR valve shortly after purchase, but there was a known problem with the early ones on the 12-valve engines overheating and burning out a core plug at the bottom of themselves. One new coilpack too. Probably a few other bits and bobs I've forgotten.

I did a compression test recently and got the same 15-16 bar readings as when we acquired it, so encouraging really. As far as I know it's on the original timing chain, so I wouldn't be surprised any time that lets go.

 

Relevantly the cat was looking borderline at the last MOT, one of the CO figures was near limits, so I swapped it out for an aftermarket one.  MOT time again now in the next few weeks, it'll be interesting...got a spare genuine low-miles secondhand one at the ready in case it fails on that.

[Morris8]

Thank you Wino. If I can get my HTP Fabia anywhere near the mileage of yours I'll be more than pleased. Reinforces the point that no matter how good vw504 might look in terms of spec., there's plenty of examples showing that, in practice, 502 seems to do absolutely fine!

[Morris8]

As an addition to this thread, I thought I’d add a piece about some extra research I’ve done.  The particular issue that drew my attention was the proposition that longlife oils like vw504 spec. might actually damage your engine in the long run(in relative terms).  As I said in my original post, if you look at basic specs. (like Lubrizol and oilspecifications.org), you might expect the contrary to be the case; i.e. you’d expect longlife oils to outperform more standard specs oils.  However, at the same time, I’m keenly aware that, in the end, what really matters is what happens when you go out of the laboratory and test the oils in real cars, on real journeys.

                As I also intimated in my posts, one of the main problems in evaluating the characteristics of longlife oils is separating the effects of the oil from the service interval. If you only use longlife oils on extended intervals, and extended intervals lead to more engine failures, then inevitably there will be a correlation between engine failures and longlife oil use.  Anyway, rather than again going over endless posts on this on various discussion websites, subjective personal opinions,  and claims made by various manufacturers, I decided to look myself to see if there is any scientific literature that could help. I was particularly interested in scientific/engineering papers that had used actual vehicles on roads. I accessed these mainly through my university library which has papers for the Engineering Faculty.        

                To summarise, my first main finding was that, notwithstanding a few anomalous reports apparently showing that some oils might actually improve a little with age up to a point, there is considerable empirical support in the engineering literature for the idea that stop-start short journeys, where the engine never warms up properly, play havoc with the oil (no matter what its quality). Moreover, even with modern synthetic oils, a severe or even dangerous degradation in the oil can occur with this kind of driving within just a few thousand miles (and the degradation starts almost immediately). Style of driving is thus very critical to the rate at which oil degrades. Another finding I came across is that timing chains are particularly susceptible to wear through carbon/ soot formation (which interacts with additives like zinc) which can accumulate very quickly as the oil ages, especially in gdi engines (TSIs on extended intervals? ).  Moreover, these damaging particles are, in the main, too small to be captured by the oil filter. These findings, of course, will hardly be news for most members of this and other motoring forums, but it’s nice to know that these ideas are not just subjective opinion or oil ‘myths’.

However, I could only find one paper that looked specifically at longlife oils (see,  J. Kral jr. et al., 2014, Degradation and chemical change of longlife oils following intensive use in automobile engines. Measurement, 50, 34-42). In this, they examined the characteristics of longlife oils in a number of cars (petrol and diesel) driven in various ways for various mileages. Although, in my opinion, there are some issues with the sampling and interpretation in this paper, the conclusions definitely give one food for thought. The main finding was that the oil evaluation sensors in the cars they looked at (BMW and VAG) significantly underestimated the amount of oil degradation that was taking place. In other words, irrespective of driving style, the longlife oils they looked at were severely degraded long before they were officially due for renewal. In fact, so poorly did they perform that the authors concluded:

On the basis of results obtained, the use of longlife engine oils is not recommended for the interval defined by the oil manufacturer…. We recommend careful consideration of the use of longlife engine oil fillings under negative conditions since the use of standard engine oil could be much more favourable (p. 41).  

I’m not quite sure how they arrived at the second part of this conclusion, or even if they used a vw504 oil specifically (though I guess they did). However, unless I or anyone else can come up with scientific/technical papers to the contrary, for the moment at least, that’s enough for me. For my next oil change I’m following the advice of Roottoot and Wino putting good old Quantum Platinum vw502 in my Fabia. Thank you for your input guys!  

[Morris8]

Just to clarify, in a nutshell, my interpretation of Kral  et al's conclusion is that even if you're using long life oil, if you're using a variable (extended) service interval based on the manufacturer's  recommendation, you're asking for trouble no matter how you drive. No surprises there. However, it's also the case that if you're using a fixed interval schedule (because of severe driving conditions) you're better off with a more conventional oil. Now that is interesting.

 

They don't actually go into why the latter is the case, but this thread is long enough already without speculating about that!