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Discussion Starter · #1 ·
Hi everyone! New Bolt owner as of two months now. Haven't had much reason to look under the hood. Decided to take a good look finally yesterday and noticed a couple of yellows X's in what appears to be grease pencil on "engine" parts. I'm guessing this is really nothing... but now I can't stop wondering why these marks are there. No problems with the car that I am aware of. Brand new 2019 Bolt LT.

Does anyone know what these marks could be for?


4,480 Posts
They're QC check marks.
Most likely.

Side note: I've attended Tokyo Motor Show 5 separate years (it's once every 2 years). At least one time, I came across a booth showing tools that relate to I don't remember the name of the company but they were along the lines of which I found by Googling for poka yoke tightening tool mark. To quote from the copy at that page
Human tightening errors are the most common cause of trouble involving bolt tightening. We supply wired and wireless devices designed to prevent human tightening errors by controlling tightening count, and marking devices that automatically leave evidence on the heads of bolts and small screws indicating they have been tightened properly to the set torque.
That's exactly what the tools did.

Anyhow, Tokyo Motor Show 2019 is end of Oct to beginning of Nov this year: If you like cars, I highly recommend allocating two days to the show. Besides the automakers, there are tons of suppliers there (e.g. Denso, Aisin, Calsonic, Jatco, Hitachi auto parts, Valeo, etc.) + various tool companies. You might find the company that made the gauge cluster, headlight assembly or door panels in another car.

If you plan on going to Japan, consider moving your trip to coincide w/TMS. :) I've posted about the show before at

The booth babes are a plus, as well. :D

(I'm actually a Japanese car guy. The Bolt is the first American-branded car I've personally bought. We've had GM vehicles in the family before but uhh... they weren't very good. :()
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