oil overfil tech question

[Pasophisto]

As a veteran of the overfill issue, I have two questions:

1.When one overfills the oil and that results in the smoking issue, where does that oil actually go? How much goes in there, how does it get in, and how does it get out?

2. Why did Porsche not change the mark on the dipstick if filling the oil tank even to the middle of the range on the stick is too much? How much could it have cost to put a new mark on the dipstick of future cars once the issue became known? What am I missing?

Thanks
Sheldon

[HarryD]

Q. What am I missing?

A. When do you check the level. Air cooled 911's are odd. You check level ONLY when the car is at operating temperature (around 180 or do), on level ground and idling. If you are checking it when cold and not running, you are at risk of overfilling due to how the dry sump oiling system works.

[DRACO A5OG]

+1 also per owners manual from PAG

[JAR0023]

I think what OP is trying to ask is: If all the cool kids have figured out that you should only fill to you reach the half way point between the two marks, why didn't Porsche change the upper mark so that full is full and not over full. Confused?

I was until I learned that tidbit. If I fill my car to the top line (hot/level/idling) it will drink that first quart like a alcoholic on a two day bender. Once the oil level reaches the middle ground between the two marks it stabilizes and I'm good to go for another 1200 miles before it drops to the bottom mark. Then once it gets close to the bottom mark it will hang there for a long time. So, why does Porsche place the full line at a point where plenty of cars will spit that last quart over into the intake? Why not make the middle point "full"?

I think it goes back to erring on the side of safety. Too many people don't pay attention to their oil level. Not so much now when they are 27 years old and owned by enthusiasts but when they were new, yeah. Better to have them drink a little oil than run too low. -J

[Rekoob]

I was until I learned that tidbit. If I fill my car to the top line (hot/level/idling) it will drink that first quart like a alcoholic on a two day bender. Once the oil level reaches the middle ground between the two marks it stabilizes and I'm good to go for another 1200 miles before it drops to the bottom mark. Then once it gets close to the bottom mark it will hang there for a long time. So, why does Porsche place the full line at a point where plenty of cars will spit that last quart over into the intake? Why not make the middle point "full"?

i can agree.. i was confused by this, as i had never heard about this. good to know.
glad someone asked the question! ill be sure to keep a closer eye on mine now.

[dienstuhr]

Originally Posted by JAR0023

I think what OP is trying to ask is: If all the cool kids have figured out that you should only fill to you reach the half way point between the two marks, why didn't Porsche change the upper mark so that full is full and not over full. Confused?

I was until I learned that tidbit. If I fill my car to the top line (hot/level/idling) it will drink that first quart like a alcoholic on a two day bender. Once the oil level reaches the middle ground between the two marks it stabilizes and I'm good to go for another 1200 miles before it drops to the bottom mark. Then once it gets close to the bottom mark it will hang there for a long time. So, why does Porsche place the full line at a point where plenty of cars will spit that last quart over into the intake? Why not make the middle point "full"?

Every car or bike I've ever owned has had a dipstick with two marks, and you are expected to maintain the oil level "between" these two levels. Most people maintain the level about halfway between the two marks. As long as you do so (i.e. it's over the bottom mark but below the top one) the oil level is thought to be adequate.

I think that maybe the OP's problem is semantic... don't think of the top mark as indicating "full" and being the desired state. It's not like a gas tank; it doesn't need to be "full". All it needs is to have the oil level maintained between the two marks - that's all.

Cheers

d.

[Jdub]

I can advise that any SC owner who has experienced overfill be sure to clean the rubber tube to plenum, the plenum, then throttle body of any evidence of oil. Be sure to open the airbox, clean this, and remove oil from the sensor plate (you don't want that "heavy" with oil since that changes running characteristics).

Yeah, it's another 911 handshake. Eventually it all soaks in and you're good!

[Dodge Man]

Originally Posted by Jdub

I can advise that any SC owner who has experienced overfill be sure to clean the rubber tube to plenum, the plenum, then throttle body of any evidence of oil. Be sure to open the airbox, clean this, and remove oil from the sensor plate (you don't want that "heavy" with oil since that changes running characteristics).

Yeah, it's another 911 handshake. Eventually it all soaks in and you're good!

2nd it is in the air box if you are smoking. My first SC motor conversion did not have the hardware between the oil tank & the air box thus giving a tank overfill a straight shot to the air box(anything above touching the tip of the stick). A body shop overfilled the crap out of the motor once because the oil light flashes when the parking brake is engaged(motor running) on a 73. My 83 SC motor has the OEM crankcase ventilation hardware and works fine with the oil 1/2 way up the stick. Just a bit of cleaning & you should be fine.

[S2GART]

To figure out how much needs to be added, just do some basic math. The owner's manual tells you how much it is from the low mark to the high mark. Now divide that by 2, and that gives you the middle amount on the dip stick. So, if your oil gets low, you will know what approximately it needs to get to the middle point.

[richuam]

You check level ONLY when the car is at operating temperature

[A horse with no name]

For those that don't know- Between the minimum and maximum marks it will take 2 US quarts - 1.9 litres