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Just wondering,

Would a reading of the oil dipstick be inaccurate if the cars' angle is off?

This could be to either sides. For example: Parked with the right wheels on the sidewalk. Right side being higher than the left or vice versa.

Also, how about if you're parked on a (steep) mountain? Front being higher than the back or vice versa.

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  • It pretty much always matters. Some engines are more tolerant to slope than others. Subaru EJ253's literally have to be near perfectly level or the dipstick is utterly useless. I've had numerous Ford's which were perfectly fine with a mild slope. YMMV, but you should always try for level when checking.
    – NitrusInc
    Commented Apr 16, 2018 at 12:39

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Yes it does matter, though to what extent is going to be dependent upon the vehicle in question. To get a proper dipstick reading, the car should be on level ground and in most cases without the engine running.

The reasons why it matters is because every engine has an oil pan/sump (note: we'll not talk about dry sumps in this instance). The sump may be of different levels and/or position relative to how the engine sits in the vehicle. Some engines sit front to rear in the engine bay, where the sump could be to the front or to the back of the engine. If the car were on an uphill slant with the sump in the front, some of the oil may have drained to the rear of the pan where the dipstick won't pick up a proper read and may appear low. With the same engine, where the vehicle is pointing downhill, the oil level may appear high.

There are a lot of reasons why the reading may be off if the vehicle is not sitting on level ground. Making sure the vehicle is as level as possible will give you the best results, though sometimes it may not be available and you'll have to make due.

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  • Perfect, Thanks Paul! I just topped up my oil yesterday as it was parked on the sidewalk (with only the right side up), thinking if the reading could've been off.
    – Paramone
    Commented Apr 16, 2018 at 12:12

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