As title really. I've read on here before that in some circumstances 5w40 would be more suitable than the standard 10w40.


not looking for brand recommendations at this stage, more an understanding of which grade would be better suited.

16v 5w 40 fully synth

dave said:

16v 5w 40 fully synth

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Castrol website says 5w40 full synthetic. Carparts4less.co.UK has their brand for 12.50 delivered. I've been using it and without some sort of testing equipment it's been fine in my 1.2

I use Silkolene Pro-S 5w-40 just because I had a couple of 5lt bottles from my old Subaru, I may switch to something cheaper, what do you recommend?

I personally used 5W30. Ambient temperature in Derbyshire rarely hits 30C and is more often 5C versus 10C - so my logic is to have the oil's constant viscosity weighted towards the lower temperature.


You could but 0W40 if you really wanted, but it's dear.

AB100 said:

I personally used 5W30. Ambient temperature in Derbyshire rarely hits 30C and is more often 5C versus 10C - so my logic is to have the oil's constant viscosity weighted towards the lower temperature.

You could but 0W40 if you really wanted, but it's dear.

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As far as i understand the "30" part is the viscosity at 100 -120c it shouldnt make any difference with the ambient temprature as its controlled on the thermostat. 5w30 vs 5w40 just means youre choosing to run a thinner oil at running temp.

Unless you go well out of spec though i cant see it makes much odds. And in UK the temperature range seems fine for a lot of multigrades.

As above 5W40 full synth.

gr J

I've been using Halfords fully synthetic 5w 40 oil, I paid £12 for a 4 litre bottle as it was on a special offer. It is not quite FIAT spec but the car is out of warranty and the FIRE is just an old basic engine I can't see it causing any issue.

With more modern engines with tighter tolerances it probably makes more of a difference. I do always use fully synthetic oil though as it is a lot less prone to sludge etc.