Dipstick is not linear!

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My entire dipstick represents only one quart of oil out of its 4qt capacity (Toyota 5sfe) after all the oil changes on this Toyota I always just dumped in 4qts and that leaves it slightly overfilled, so this time I put in 3 qts and checked the dipstick, nothing shows on it until you add the last qt.
 
Originally Posted By: zach1900
My entire dipstick represents only one quart of oil out of its 4qt capacity (Toyota 5sfe) after all the oil changes on this Toyota I always just dumped in 4qts and that leaves it slightly overfilled, so this time I put in 3 qts and checked the dipstick, nothing shows on it until you add the last qt.


That's so you freak out when you're a quart low.
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I've done something similar. Oil changes at home are done about a half quart less than the spec. Then I check the dipstick or level sensor level and it generally is right where I expect it.
 
Originally Posted By: Quest
dipstick not linear? that's because the shape of the oilpan is not rectangular/square/cylindrical.

Q.


Precisely!

If the oil pan was a box, then the dipstick would be linear, but the cross section of the oil pan varies with depth, so the volume per unit of length on the dipstick varies...

You were surprised to find this out?
 
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I just embarrassed myself, I should have said I expected each qt. (out of a 4qt system capacity) to raise the level on the dipstick 1/4 with the 4th qt reading full.
Originally Posted By: Astro14
Originally Posted By: Quest
dipstick not linear? that's because the shape of the oilpan is not rectangular/square/cylindrical.

Q.


Precisely!

If the oil pan was a box, then the dipstick would be linear, but the cross section of the oil pan varies with depth, so the volume per unit of length on the dipstick varies...

You were surprised to find this out?
Originally Posted By: Astro14
Originally Posted By: Quest
dipstick not linear? that's because the shape of the oilpan is not rectangular/square/cylindrical.

Q.


Precisely!

If the oil pan was a box, then the dipstick would be linear, but the cross section of the oil pan varies with depth, so the volume per unit of length on the dipstick varies...

You were surprised to find this out?
 
Now, the Packard's oil pan is roughly constant in cross section...

But Packard thoughtfully provided an oil level gauge built into the side of the block, and one merely has to look at the arrow, to know the level, and how many quarts might need to be added...
 
BMWs don't have a dipstick. Problem solved. Other problems arise with weird sensor biases and noise though. More problems created.

About non-linear dipsticks, my girlfriend thinks those are kinda cool.
 
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None of you guys are old enough to remember when fuel gauges were non-linear.
 
What about on Chevys? Ive yet to understand why there are a few holes on the dipstick. Im not sure if each represents a quart up to its six quart capacity.

I always have learned that on cars the lower to upper mark was always a quart. On big rigs it represented a gallon.
 
Originally Posted By: Leo99
None of you guys are old enough to remember when fuel gauges were non-linear.


Was just going to say the same thing. Some may still not be.
 
The difference between L and F on the dipstick is 1 quart....and it is linear...that is, add 1/2 qt at L and it will raise the level on the dipstick half-way to F.
 
Originally Posted By: Leo99
None of you guys are old enough to remember when fuel gauges were non-linear.

My 2003 Saturn ION was the first car in my entire family with a gauge that behaved in a linear fashion.

Every car before it had a needle that would drop rapidly once the car had a 1/4 or lower reading.
 
Originally Posted By: zach1900
I just embarrassed myself, I should have said I expected each qt. (out of a 4qt system capacity) to raise the level on the dipstick 1/4 with the 4th qt reading full.

That's not how it works at all. As was mentioned earlier, normally the difference between "Add oil" and "Max" on the dipstick represents around 1qt or 1 liter.

Now, on some engines with fairly small oil capacity, that can represent as much as 30% of your entire oil capacity. On other engines, this might be as little as 12%.
 
The flexible dipstick for my Toyota Landcruiser is about a meter long and snakes from one side of the 5.7L block to the other.

Not sure I'd trust it for precise measurement.

But the engine holds 8 quarts so it's wouldn't be the end of the world if it went a quart down.

But it's a Japanese built Toyota and never goes a quart down.
 
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