My oil choice & thanks to all who advised

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Feb 27, 2004
I have now decided on GC ("Formula SLX" over here, not to be confused
with "SLX II Longlife") for my Xedos. I arrived at this decision
- my Mazda Xedos manual recommends only a 30-wt whereas my wife's Mazda
MX5 manual indicates that several oil grades may be used. Therefore I
wonder whether this has to do with under-dimensioned oil passages in
the Xedos V6. This view was probably influenced by reading about Mitsubishi FTO(?) V6s
that can dry out their sumps if the oil is too thick to circulate at the
correct rate. I have therefore decided to err on the side of (some
would say extreme) caution.
- There are any number of 40 & 50 wt oils available here (UK), but only very
few 30-wts (no 20-wts at all.)
- 5W30 is only available in various brands as ACEA A1 or A5 and I am
have no reliable way of confirming that my engine can cope with this. The local Mazda dealership appears not even to understand viscosity ratings (told me M1 0W40 "is thinner than 5W30!")
- The same applies to Saab 0W30 & Shell Ultra Helix 0W30, also
available locally.
- Cheapo 10W30 dino is available and would be acceptable (ACEA A2 or
Ford WSD-M2C904-B2) but I would like to be able maintain the standard
Xedos OCIs of 9k miles as the car does ~25k/annum. I don't trust these
oils to hold up for more than 3k nor do I trust them to hold up under
autobahn conditions (continuous WOT.)
- GC was the only other available option that fitted the bill, being ACEA A3. So that is what I bought.

It is unfortunate that GC costs >= £10/ltr unless a discount can be

Many thanks to all who commented on/answered my questions about this car's requirements in previous threads.

If you have seen many of my posts it should not surprise you to hear me say, "What an EXCELLENT choice!" Hope it gives you 100s of 1000s of miles of GREAT service!
Maybe there is an arbitrage opportunity for someone creative to export GC from the states back to the EU. The retail price here is under $5/quart.

$5/quart * 0.946 litres/quart * 0.545 £/$ = £2.578 / litre.

Thus GC appears to be ~75% cheaper in the USA than in the UK at retail.

No wonder Castrol labels the bottles "For Sale In North America Only"

Perhaps we can work out a swap, UK prescription medicines for US synthetic motor oils!

As I told G-Man II in another thread, I remember paying around €15-18/litre (of course it was DM back then) for Shell TMO when I lived in Germany in the early 80s. We are so fortunate price-wise when a Euro oil makes it to our shores and stores.
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