Which 5W-20 oil do I get?

[HemiCommander]

I have recently acquired a Jeep with the 5.7 Hemi which very specifically requires a 5W-20 oil. It turns out that this is a rather obscure weight of oil that is very expensive and difficult to find in the UK. I would like to use a fully synthetic oil but Chrysler also recommend using an oil that meets their MS-6395 specifications. I need just under 7l apparently and I am willing to pay decent but not stupid money (<£100 for the oil would be good).

The options I have found so far are:

• Mopar 5W-20 : This looks good as it's specifically for Chrysler products and meets the MS-6395 spec but doesn't seem to be fully synthetic. Cost = £80.
• Fuchs Titan fully synth 5W-20 Cost £80
• Motul Specific 5W-20 fully synth Cost £110
• Castrol Edge Professional 5W-20 fully synth Cost £65. This is from ECP so rather convenient too.

So which of the above would people recommend or are there any other suggestions? I would like to use Mobil 1 but I can't find it anywhere in the UK and it seems silly ordering oil all the way from the US of A.

Thanks in advance for any pearls of wisdom.

[Krikkit]

Are you sure it can only be run on 5w-20? Sounds very odd for a manufacturer to state only a single grade of oil is usable. They usually have multiple types depending on the region of use (thinner for colder climates etc).

ETA: Ah, it needs to be 5w20 for the clever multi-displacement thing, bugger!

I'd go for the Mopar or Fuchs.

Edited by Krikkit on Wednesday 27th November 18:33

[MJK 24]

The new Ford Ecoboost require 5w20 so it'll soon become widely available in time.

[VinceM]

MJK 24 said:

The new Ford Ecoboost require 5w20 so it'll soon become widely available in time.

And most will only use 5W20.

To the OP, have you checked in the handbook to see if any alternative viscosity can be used?

[ch427]

not used the products personally but got to be worth a look.
http://www.lucasoil.co.uk/store_item.php?product=1...

[Ozzie Osmond]

All the 20 does is eek out the final teeny bit of fuel economy. It's not as if that engine is the fanciest in town and it should be fine on 30. But why not just buy the recommended oil?

[V8RX7]

Are you sure it needs the 20 ?

Generally (but not always) manufacturers specify a low viscosity oil to meet efficiency targets etc and they are actually better protected with a thicker oil.

I'd check on a Jeep specific forum but I'd be surprised if a Yank engine is that fussy and 5W 30 couldn't be used

[HemiCommander]

The handbook is quite specific that 5W-20 must be used or the multi-displacement system may not function correctly. I have a suspicion that the oil currently in it may not be correct and that it may not be functioning correctly. As it is so unusual and difficult to get hold of I thought a garage might have just bunged whatever they had in it when they serviced it. The fuel economy is pretty shocking so I want to change to a synthetic of the correct grade to see if any improvements can be seen.

ch427 said:

not used the products personally but got to be worth a look.
http://www.lucasoil.co.uk/store_item.php?product=1...

That is a good looking option, I shall look into it in more detail.

[HemiCommander]

Well having done some more reading it seems the Mopar oil is indeed not fully synthetic, which leaves it looking rather expensive for a conventional motor oil. I am leaning towards either the Fuchs, the Castrol or the Lucas at the moment, they seem to offer very similar price and specification. Anyone have any more input for me to consider?

[PanzerCommander]

I have been using Lucas fully synthetic 5w-20 in the Mustang since I bought it - no problems with it at all.