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Just hate leaving my car anywhere so I was thrilled.
This -^ X 991.
What folks haven’t asked is why I didn’t “let” the paint shop R&R and disassemble/reassemble the apron.
After ~25 years of working on 928s I have seen no evidence that would enable me to trust a body shop to do disassembly/reassembly on a car I gave a crap about.
I have a 928 in the shop right now where the body shop reassembled the (rather complicated) light-lifter mechanism with some parts upside down. Rather than taking it apart and doing it right, they glued various shims and extensions on parts to get it to sit right at rest and full extension. FFS!
My 991.2 TTS was in the shop for 3 months -- redoing the work that was done previously. Poor paint respraying front bumper cover, then found clear coat overspray which had to be removed and ceramic coating reapplied, then found more rock chips on delivery ('thankfully PPF helped protect paint), then reapplication of PPF and ceramic coating twice due to poor application, etc. This done all through the Porsche dealership. Finally got it to back to the point where it should have been the first time.
However, I also had paint correction/ PPF, tint, ceramic coating on our new Tesla at Concours (Torrence CA) who did a magnificent job!
Hit and miss I suppose. Just glad to be out of that vicious cycle!
Today I did the Tower's of Hanoi (https://en.wikipedia.org/wiki/Tower_of_Hanoi) problem and got the Turbo into a work bay. It's due for oil, filter, and brake fluid. And, of course, to put the front apron back on. So, up it went and wheels off.
I then looked at the sorry state of my heat exchangers and said to myself: "Self... while you're here you might as well clean those since, you really, really hope not to have to take that apron off again for quite a while."
If you do this... bring a !@#$ing lunch.
Here's the left-side condenser before...
... and after way, way too much time spent cleaning.
The radiator seems to attract debris like $h1+ attracts flies. In this shot I've cleaned 1/3 of it.
The good news is that all those shrouds come off easy. I learned a trick for dealing with 15-zillion clips when I was doing the front apron.
So while all that-^ is on-going I'm letting DDG (that's my Turbo's name) drain her oil. For reasons that I won't go into, I decided to collect some data on oil drain amount versus time.
"The Book" indicates a total dry capacity of 10.4 liters and 7.5 liters for an oil change with or without a filter. Note that by "The Book" 2.9 liters of oil remains in the "engine" when doing an oil change.
The first step was to drain the sump for exactly 20 minutes into a empty oil catch pan. After everything was done, I drained the the oil from the pan into two 5 liter containers with one filled to 4 liters. The second was filled from the pan until the oil was dripping. That second container filled to almost exactly 2 liters.
After exactly 20 minutes (within a few seconds) I swapped the catch pan for a 1 liter measuring cup into which I allowed oil to drain for exactly 10 minutes. Then I swapped in a second cup into which oil drained for 1 hour. Then a third cup into which oil drained for 3 hours. Then, for 3 more hours I allowed the sump to drip into a fourth cup.
Data:
20 minutes of draining yielded 6 liters.
The subsequent 10 minutes yielded 300 milliliters.
The next hour of draining yielded 800 milliliters.
3 more hours of draining yielded 600 milliliters.
The last three hours - for a total of 7.5 hours - yielded an additional 100 milliliters.
Chart:
Note that in order to drain the "required" 7.5 liters "the book" calls for drain time must be about 220 minutes (3 hours and 40 minutes.)
I for one am not surprised that dealers have been having problems getting oil fill levels "down."
Ok, that is the best oil drain report that I have ever seen! I am guessing that you are a fellow engineer (if not, consider yourself an honorary member). I was surprised to see how much oil was collected during the second and third time intervals. My sense is that oil changes at dealerships (or at Indy's for that matter) don't surpass 1 hour of draining.
Ok, that is the best oil drain report that I have ever seen! I am guessing that you are a fellow engineer
From time to time. And a piece of paper that says IR1.
Although a *real* engineer could determine the final viscosity of the oil that I drained.
Originally Posted by Greg2010
My sense is that oil changes at dealerships (or at Indy's for that matter) don't surpass 1 hour of draining.
I wouldn’t know. But I’d bet on 20 to 30 minutes; Bays don’t generate revenue unless works’ being done in them. Oil dripping is not revenue generating.
Hahahaha! This is the best! @worf928 , I think I like you! 🤣
Also...how the heck did you get your radiators so clean?? I've used a combination of things before and still couldn't get them to look like yours! Great job. DDG thanks you!
So while all that-^ is on-going I'm letting DDG (that's my Turbo's name) drain her oil. For reasons that I won't go into, I decided to collect some data on oil drain amount versus time.
"The Book" indicates a total dry capacity of 10.4 liters and 7.5 liters for an oil change with or without a filter. Note that by "The Book" 2.9 liters of oil remains in the "engine" when doing an oil change.
The first step was to drain the sump for exactly 20 minutes into a empty oil catch pan. After everything was done, I drained the the oil from the pan into two 5 liter containers with one filled to 4 liters. The second was filled from the pan until the oil was dripping. That second container filled to almost exactly 2 liters.
After exactly 20 minutes (within a few seconds) I swapped the catch pan for a 1 liter measuring cup into which I allowed oil to drain for exactly 10 minutes. Then I swapped in a second cup into which oil drained for 1 hour. Then a third cup into which oil drained for 3 hours. Then, for 3 more hours I allowed the sump to drip into a fourth cup.
Data:
20 minutes of draining yielded 6 liters.
The subsequent 10 minutes yielded 300 milliliters.
The next hour of draining yielded 800 milliliters.
3 more hours of draining yielded 600 milliliters.
The last three hours - for a total of 7.5 hours - yielded an additional 100 milliliters.
Chart:
Note that in order to drain the "required" 7.5 liters "the book" calls for drain time must be about 220 minutes (3 hours and 40 minutes.)
I for one am not surprised that dealers have been having problems getting oil fill levels "down."
Just wanted to confirm: Is this starting with the oil at operating temp?
Sorry, oil... Seems odd to me that when drained that long, there's still some in there.
No matter how long you let oil or coolant drain there's always plenty left.
Why?
For oil in particular it's because it "clings" to surfaces. One of the aspects of modern oil is that it will never, ever completely run off. And that's a very good thing.
There are also various passages, nooks crannies that don't "point down." (*)
There may also be lines running from the block to heat exchangers.
In the 991 there's a vacuum pump at the same level as the pan that doesn't drain.
Imagine 6 blenders, half-filled with oil, where the 'top' of the blender is a 3d-maze. Turn the blenders on. Then take the tops off an put them on the counter. Dump the containers and set them upside down on the counter.
The containers will drain except for a film. The "mazes" will never drain.
(*) And we know that there's a bunch of oil in the right-side turbo inlet hose
Here's a real world example.
This 928 motor, when the picture was taken had, had the oil drained for *years.*
Yet, you can still see drops of oil on the main bearing cap nuts and girdle bolt heads (and in the drip pan.)
If you drain a 928 engine, let it sit for weeks dripping, then turn it 90° on the engine stand it'll pour a quart of coolant and a pint of oil. If you then turn it back upright and 90° to the other side it'll pour out another quart of coolant and a pint of oil.
The only way to get all of the fluids out is to chemically clean *everything* touched by fluid.
A 928 radiator will drip coolant for weeks after it's drained (3d-maze inside.)
Which brings up another point: the 991 Turbo radiator is surprisingly small for the power output. No doubt a more efficient matrix and the fact that it's hanging out way in front in the bug stream rather than tucked under a svelt nose. Heh... I think I'll take a picture of them side-by-side in a bit.
FYI - you likely already know, but the oil drains more quickly at temp. Would be interesting to see the flow at 175*+
My prediction is that you will get more out in the first 20 minutes but it will take longer to get 'the rest' out.
I may capture that data next time around. But, that'll be 5 or so months until CarChick's 991S 3.8 is due for oil.
Once, a long time ago, I had a stream of 150+°F oil run down my bare arm to my armpit.
And, I have yet to hear of an explanation for draining the oil 'hot' that is, to me, epistemologically valid *except* that it reduces drain time. That only matters when you are looking at $/bay/hour. When I'm doing oil, I'm always doing something else too, so drain time is pretty irrelevant.
05-19-2023, 03:59 PM
