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Discussion Starter #1
Hi everyone!
Oil change time has come for my 92 Seville with the 4.9 engine with around 60000 miles on it. The service manual says API SG 10W30 and
SAE 10W40 IS SPECIFICALLY NOT RECOMMENDED
I'm OK with it, except that here in Switzerland (and most of Europe I think), most mechanic will say something like "You mean 10w40 right ?"
To put it simply, 5w30 and 10w40 are king and queen here. 10W30 is basically unheard of except for expensive special full synthetic for GDI stuff or small bottles for bikes "with oil bath clutches". Or lawn mower stuff...

Looking to an old service bill I found in the car when I bought it, they put in... 10W40. :cautious:

Car ran fine though...

Doing more research led me to this one, https://www.motorex.com/en-us/classic-line/motor-oil/evotec-sae-10w30/
Made for classic vehicles but it is only API SF.

What do you think of this ?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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67,166 Posts
Every oil you find here - now - is API SN or API SN+, regardless of viscosity range. SG went obsolete in about 1993 - 1994. SF used an even more obsolete anti-foam and anti-scuff additive package.


What is the ambient temperature range you drive in - degrees F ? If you don't regularly drive at below 10 degrees F then 10W-40 should be OK with a 45 - 60 second warmup fast idle period.
 

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Discussion Starter #3
Thanks for the very fast answer!
The temperature range is roughly 15F to 100F through the year here. Upper or lower is exceptional.
So according to you, plain Jane dino 10w40 would do the job ?
Any thoughts on why Cadillac specifies against it in his service manual ? I am curious about that...
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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67,166 Posts
That service manual was written 28 or 30 years ago - oils have changed radically during that time. Today, I would rather run either a 10W-30 or -40 name brand synthetic oil in that engine - it is generally taught that synthetics have better cold flow characteristics and tend to remain in bearings longer under storage conditions - less chance of a "dry start".

A 10W- XX oil is 10W when cold, slowly changing its viscosity index as the oil warms to about a 200 degree operating temperature.
 

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2014 ELR
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I would suggest 5W30. It will flow quickly at cold startup, and behave the exact same as a 10W30 when hot.
 
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