When I had my 1k service done I noticed that my dealer used 10w-30 oil which differs from the 5W-40 that the manual states. They said that's what they've used on all the cars they'd serviced and is "better due to our hot climate." Didn't make sense to me (30 better than 40 in a hot climate?...I don't think so). So I sent an email to LCOA to see if there would be any issues and to confirm that my warranty would not be in jeopardy. Their answer is as follows (and I actually got a phone call from them, too. Now THAT's customer service):
Good afternoon Mr. James
Thank you for your email, as per our telephone conversation today, Lotus
Cars USA only recommends that a fully synthetic 5W/40 oil is used after
the running in period oil has been drained at the aftersales service.
I'm sure that no damage will occur due to the use of Mobile 1 10W-30 as
used by [your dealer], but technically they should have only used 5W/40 as
per the recommended lubricants page as noted in the owners handbook.
[Your dealer] is rectifying this situation with their oil
representative as we speak and has said that they will happily carry out a
free oil change when they have the correct grade oil
I would recommend calling them in a week or so if they have not contacted
you by then.
Regards,
Andy Plant
Warranty Manager
I figure, if the factory says use 5W-40, that's fine with me. I decided to go ahead and put Mobil 1 5W-40 in myself rather than go thru the hassle of going all the way back to the dealer, which is kinda far away.