Help! Opponauts: lend me your motor oil expertise.

Illustration for article titled Help! Opponauts: lend me your motor oil expertise.

I’m doing some extreme pre-Spring cleaning and sorting through old receipts, invoices, etc. Coming across various auto stuff, I noticed something on my invoices from the dealer: in 2017 - which was the major bill with the timing belt and 90k service — the engine oil called out was:

“6 MOBIL1 5W30 SYN

No I’m no brain operator, but it seems to imply: 6 quarts of Mobil1 5W30 Synthetic Oil, as the oil capacity is in fact 5.7 quarts. But looking at the two invoices from 2018 and 2019, they call out a differently oil entirely:

“6 MO 5W20 MOTOR OIL

Hmm, no SYN tag, implying it was in fact conventional. Notice also, even the weight of the oil has changed for some reason. The factory oil is 5W30... why the heck have they used 5W20 on my last two changes?

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As a consumer, there exists no point in putting a customer in the database with all your account info and payment history and viewable electronic invoices, etc., if they can’t even bother to verify what OIL they have been putting in my car for three years. So that’s my rant.

That all aside, short version is as follows: all signs indicate: in 2017 I had full synthetic oil. In 2018, it switched back to conventional and has been so since — AND at the “incorrect” weight.

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So — what do you think I should do from here? Keep riding with 5W20 conventional? Go back to factory 5W30 conventional? Or return to 5W30 synthetic, and is there anything else I should be wary of before I just start dumping that in?

Thanks as always for your time.