Reading dipstick

[SpenceRx]

I checked my oil today for the second time. I’m worried about overfilling it. The dipstick is a bit tricky to rear as my oil doesn’t seem to leave a very defined line.

Checking oil on flat surface, engine up to temp and running.

Photo 1 was clearly on the low side so I added oil. Then it’s reading somewhere in the middle so called it good but definitely hard to see a distinct line.

What volume moves it from min to max on the dip stick?

[PeteKz]

IME, about one quart moves it from Min to Max. Note that the oil level varies even with the engine fully warmed up and idling, which is the way you are supposed to measure it. I've seen about a half quart difference. Why? Beats the shirt out of me. It just sometimes reads higher or lower.

[Schulisco]

From the manual of a '82 SC:



Experience tell that filling oil only up to half dipstick makes sense, otherwise oil may leave the engine. Is your's a 2,7? IIRC the oil tank has same size on both 3.0 and 2.7l engines. So no differences here. Also the Carrera has no other recommendation in the manual.

[silverlock]

If it’s over the “min” marker you can give it half a quart, but I wouldn’t worry too much beyond that.

There’s another 9+ quarts of oil in the car and they can run it on ~5

You just want the dipstick to tell you there *is* oil.

[Cairo94507]

I can relate to having a hard time reading the dip stick with clean oil. I lay a white paper towel on my bench and then remove the dip stick and wipe it off and then re-insert it into the tank and then remove it and lay it on the paper towel. Remove the dip stick and you are left with a nice image of the oil level to compare to the marks on the stick.

[EC900]

@Schulisco - interesting point about regarding oil tank sizes from 2.7 & 3.0 being same. But for reference I’ve posted a couple pages for @SpenceRx in case he doesn’t have the owners manual handy.
Definitely there’s a quart difference between the two and wonder perhaps is the dipstick length or markings?
For what it’s worth, the space between my Max/Min mark is appx. 3” or 76mm on my ‘77-2.7L.

I wondered about my own {77-2.7L) and the dipstick being the proper one for the engine.
I had similar experience with a mower engine - couldnt read clean oil mark and found it had wrong dipstick, overfill and oil blew out all over !

Note - I spread the finger loop just enough so it doesn’t drop into the tube making it easier to retrieve if I can’t reach it w/o a hook

[E Sully]

I can't say what years were affected but Porsche adjusted the oil level over the years. Newer sender and dipsticks reduced full mark level, most likely to reduce oil loss at full level.
Which length oil dipstick for '74 - '89 oil tank?

[SpenceRx]

@EC900 Thanks for the reference photos. I didn’t t think to look in my book. It’s got more info than you’d expect.

2.5 litres between the hash marks is a lot!

[panama911]

Originally Posted by EC900

For what it’s worth, the space between my Max/Min mark is appx. 3” or 76mm on my ‘77-2.7L.

For what it's worth, on my 73.5 it's only about 63mm or 2.5" from min to max.
But I can't guarantee it's still the original...

Does anyone have a list of which dipstick length corresponds to which model year/ tank?

[PeteKz]

Likewise on my 1973.5. That's probably why a quart is enough to raise the level in my car, but not in a 2.7 or 3.0 car.