I have spoken to Castrol's Technical Helpline today and there technician has warned me that SLX Longlife II is NOT suitable for the Fabia vRS due to the viscosity being too light which causes premature wear and scuffing to the piston skirts. (this ties up with a warning on the bottle not to use it where 505.01 is mentioned in the owners handbook)

His advice was 505.01 is the only grade we should be using, due to it's heavier viscosity and the fixed service schedule of this model.

I mentioned that surely a higher spec oil should be better, but he was adamant that 506.01 is not suitable. He is sure that these cars do not come with 506.01 from the factory, which would tie up with the manual that only recommends 505.01.

I was going to use Longlife,but have used Quantum 505.01 PD oil instead on his advice.

Do any techies out there know for sure what the factory fill is. The plot thickens......

I have no idea what the factory fill is.

Just because one spec is called 506.01 rather than 505.01 doesn't necessarily mean that it's a higher spec oil, rather it's a different spec oil and it's the next one in the series. The higher number doesn't necessarily indicate higher spec does it ? Given that 506.01 is used in only a very specific set of circumstances it makes sense that it won't necessarily be suitable for other sets of circumstances. You should consider whether SLX Longlife II matches 505.01, which is the spec for your car. It would appear not & so using it wouldn't be a great idea.

I'm hardly one to talk about using over specced oil as I top up my Octavia 110 bhp estate with Millers PD oil (use it in the SEAT) but it DOES say that it meets the spec for the Octavia so I know I'm OK.

Errrm. im pretty sure that all fabia vRS come with longlife (read: Castrol SLX II) out of the factory. and my car was topped up by the dealer with slxII too.

If you are going by the 505.01 spec then imho millers pd-xfe is a great choice. My dealer was very sceptical about this stuff when we used it 16500 miles ago now. The first lot had to be changed after 7500, but he admitted that they had not flushed the engine and there had been a large carryover of old oil and crap. So 9000 miles ago it was changed again after a good flush, and other than turning the usual black colour is still very viscous and free running. Those who know me knows my car gets a pounding both in town, long motorway stints and the old trackday thrashing , its only about 3 months since the last serivce! I teach the son of the md at my local dealer and the service boys are keeping a close eye on the millars as its a lot cheaper than the current stuff, but is holding up better and still meets the required spec so they can use it. Personally I pay

My local car shop is getting VW's own quantum brand 505.01 PD oil from the local dealer and selling it at

I seem to remember a post that quoted Skoda technical stating that diesel Fabias in the UK were all on fixed service intervals and didn't have the required sensors to run variable service intervals using 506.01. I would therefore be very surprised if the factory fill was 506.01 as it's more expensive than 505.01.

Not very technical I know, but I've always been amazed as to how thin and 'runny' 506.01 is compared to 505.01. Someone told me that, oil gets 'thicker' the longer it's in an engine. Therefore, for variable service intervals a thinner oil is needed to start with. Sounds a bit dubious to me but if this is true then it's a bit worrying for people who do 25k between oil changes.