Auto Mechanics: how much is too much oil?

[Fotheringay-Phipps]

@Machine_Elf

The “high” and “low” marks on the dipstick provide a substantial safety margin, so being a few ounces over the top mark isn’t a big deal. If you were able to drive it home from the dealer, then you’re probably fine.

Thanks - that’s reassuring.

And leads to another question, in the other direction. I own a couple of cars which call for 3.9 quarts of oil. Frankly it would be easier and simpler to just pour in an even 4 quarts. Question is whether it’s worth the effort to avoid overfilling by 0.1 quart.

@HipGnosis

I’d be very leary if you bought the car from a non-brand used car lot. They may have over-filled it because they know the engine burns or leaks oil

It’s a possiblity I’ve thought of, but I doubt it. (They just got it in a trade last week - per CarFax - and I don’t think they would be running that level of tests on it.)

Just how are you determining that’s it an extra 1/4 - 1/3 quart?!?

Based on how much above the full line it is. The space between the min and max lines seems to be a bit over 1 quart, and I’m assuming the same ratio above the line.