I'm trying to find out which oil for my rapid so many conflicting grades from ow40 to 10w30...help please

Don't look at the grade, look whether it meets the VW oil spec in your handbook - possibly VW502 or 504 (but someone will be along to confirm).

If you want to follow VW's dictates on oil (502 00 / 504 00) then your Owners Manual will guide you, the Germans of course have to have their own system of numbers for things like oil and (difficult to follow numbers coolant) to make out there's something special, the Owner's Manual doesn't give weight range or fill capacity (why? because they don't). 

 

For my wife's 2015, 1.2 TSI, 90 petrol the Dealership(s) claimed to have used 5w-30 and then later 0w-30.

 

"Longlife" or "LL" to me are just marketing terms but if it is also a better oil than one that doesn't have those terms on the label then better to use it.  "Longlife" is supposed to be about and for longer "service" (oil 7 oil filter change) but I stick with the 9,400-mile or 12 months whichever is the sooner, I might extend the mileage if I was using a really good oil but still change every 12 months.

 

A 5w or 0w engine oil will be a good engine oil to meet the 0w and 5w specifications, of course even at these specs there are some "more equal than others" but you can get into diminishing returns and it may depend on if you want to keep the car a few years or many years and how the car is used and driven.

 

Edited 9 August, 20241 yr by nta16
typos

FYI and as an example only, this is what I'll be using if I do the engine oil & filter change next month myself on my wife's 2015 Fabia 1.2 TSI, 90, as I've used their engine oils for a few years on my (not VW) car. - Millers Oils EE Performance Engine Oil C3 5w30.

 

Millers Oils Which Oil? Oil Checker Tool - https://www.millersoils.co.uk/which-oil/

 

Edited 9 August, 20241 yr by nta16

It certainly is not 10 w 30. 

 

VW 504 00 / 507 00 for Fixed Service Regimes or Variable.  so 0w 30 FS III or 5w 30 FS III

 

Fixed Service Oil & Filter change intevals can be VW502 00 so 5w 40 FS.