Hi,
I just bought a fully synthetich oil which used to be available at 5W40 and ACEA A3 and now it is 5W30 and ACEA A1.

I have a 1998 Jaguar XK which specifies the usage of ACEA A2 and regarding the viscosity 5W30 seems to be ok as long as it is fully synthetic (for summer temperature up to 40 C - according to the manual).

Have I made a mistake buying this new stock ? what is the mains difference between ACEA A1 A2 and A3 ?

Many thanks
Nader

A3 has a better quality and has better extended drain capabilities in relation to the A1.

Personally I would not use an A1 in a XK8 Jaguar. I would use a synthetic A3-02 5W-40. The OEM demands a A2 or A3 (or API: SH).

It should be no problem obtaining a product with A3 5W-40. Few examples (guessing you're from the US???):
Havoline Ultra SAE 5W-40 (Texaco)
or even AMSOIL Synthetic 5W-40 European Engine Oil

This message has been edited. Last edited by: .:[EM]:.,

The main difference between ACEA A1 and A2/A3 is in the HTHS viscosity. ACEA A1 has HTHS viscosity value of min. 2.9 mPa/s (or min. 2.6 mPa/s for SAE 0W-20), ACEA A2 and A3 have that value min. 3.5 mPa/s. It cannot be recommended to use ACEA A1 instead ACEA A2/A3 motor oils.

I send you a link to ACEA in Belgium, it's always best to go to the source and get the complete description.
http://www.acea.be/ASB/Download.nsf/Category0Files/F5167E6B75D68AF5C1256F4600263CD9/$File/ACEA2004%20oil%20sequences-DEF.pdf

Great stuff, downloaded...!

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