[whobodym]

My engine is a 2017 FA20A (Forester XT) but this is likely just as applicable to many more Subarus. Here are photos to show just how far off dipstick readings can be, when you are not careful about wiping it off with a paper towel, and/or you do not park the car on level ground. Both these pictures were taken today in my sloping driveway, with only 60 seconds of driving between, to turn the car around, then an hour of parking to settle the oil again. My car's actual true oil level today is near the perfect "Max" upper hole on the dipstick, if I were to have parked on level ground and done a careful wipe job. My driveway slopes about 6% (3 inches over the length of a 4 ft carpenter's level). Take note how there is some chance to spot the "partly-wet" level on the dipstick without first wiping, which actually is some indication of the correct level. It varies in appearance but I can usually spot it. But I would never trust this method of interpretation to someone who wasn't a careful observer.

slope check:

 

[OutbackJon]

Sorry, but I can't take your measurement seriously unless you're using a mahogany carpenter's level. Aluminum just isn't an acceptable substitute.

 

[Mr.AC]

Dip stick meet up anyone?
In a circle though........

 

[whobodym]

Dip stick meet up anyone?
In a circle though........

depends if that's a double entendre...

 

[pieanddanish]

Dip stick meet up anyone?
In a circle though........

"I see your [dipstick] is as big as mine...
Let's see if you know how to handle it."
-Spaceballs in some other dimension

 

[bingow]

@whobodym, your point is valid. Hopefully drivers would note a slope of 6%, but maybe not 2% (¼" per foot), which would be typical for most garage floors (sloped to meet local building codes, if any). Judging from the forum's many lengthy oil/dipstick threads, a 2% slope, if unaware, would cause great anxiety, and even more such threads.

 

[Mr.AC]

Joking aside......
My drive way is on a slope as well, and even my street is on a slope. I tend to wait till I fill up at a gas station to check my oil. At lest there I know some what sure it's level. Granted if there is enough time for the oil to settle down while filling up. Some times I need to wash my windows to get a few minutes to check again.

@whobodym
It's what ever you wanted to be.... 🤩😚😲

 

[titleman]

OMG people it's not rocket science.

 

[boureesub]

OMG people it's not rocket science.

I don't know the background of @whobodym , but his little study is what I would expect of an engineer...

Engineer: Solving problems you didn't know you had in ways you can't understand.

 

[whobodym]

If anyone still really doesn't understand my 2 dipstick pictures, I could add two more, showing wiped-dipstick with car pointed downhill, and unwiped-dipstick with car pointed uphill. That's the main mental leap I was forcing you all to make. (and yes I was an engineer for a certain airplane company, but being retired now I get to focus on this kind of stuff all day long )

 

[boureesub]

Enjoyed your experiment. I have the exact same well-used level in my shop. Can't say the same for the vintage ruler.

 

[drdavidzhang]

For some cars, reading the dipstick is difficult. There are three existing common solutions， but all these existing solutions are creating permanent irreversible change to a car component. Not only is it uncertain whether the modification will work well under various different conditions, but also it may lead to unintended consequences. Why would your own modification be significantly better than that designed by experienced car manufacturers?

4 Ways To Accurately Check Oil Level On Sloped Driveway...

www.subaruforester.org

 

[GraemeHarrison]

Actually, the dipstick design was never tested by focus groups of Subaru owners. Subaru engineers decided to employ two unmarked holes as upper and lower limits, but they can be confused with positions on dipstick where the stick is put through a 90-degree bend. With other cars, the limits are marked by such twists in the dipstick, so mixing up twists and holes is confusing. I just bet that if 20 typical owners were brought in for a test, a considerable fraction would suggest other interpretations of the Subaru dipstick. The most easily understood one I've ever seen is a 90-deg twist at upper point and another 90-degree twist a lower point (an no other twists anywhere along length of dipstick) plus 'hatching' (diagonal scratch marks in both diagonal directions) between, indicating range of allowable levels. Subaru's practice of having twists 'below the bottom level' is plain confusing, IMHO.

 

[whobodym]

@GraemeHarrison I suspect the twists in our Subaru dipsticks are geometrically necessary, to get the segment of the dipstick right at the oil level, to be facing the correct direction