Condensation in 993 Engine
02-15-2017, 10:57 PM
#1
Racer
Thread Starter
Condensation in 993 Engine
When I had a PPI done on my '97 Targa in July 2013 I was told I had a small oil leak on the lower right valve cover. Last month I saw the first oil drops on my garage floor. Consequently, I took it to our local dealer to fix as well as to trouble shoot the a/c system which acted crazy last month by cycling from no fan to max fan no matter the settings.
This afternoon I got a call from the Service Dept. that the oil looked "milky" and there was "moisture" in the engine. Now, if this were a water-cooled engine, it would typically indicate a leaking head gasket that allowed coolant into the crankcase. But, of course water into the engine isn't possible with an air-cooled engine. Oil has been changed regularly. Last oil change was 11 months and 1700 miles ago with Castrol Euro Synthetic 5/40 at the shop many of us use for our Porsche's, BMW's and Mercedes.
My question is this: What do you RLers think may have caused this? Just 4 days ago we did a 200 mile round-trip on the highway. That should have cooked off any moisture from sitting in a not yet air conditioned garage too long in the heat and humidity of south Florida.
Your help will be appreciated.
This afternoon I got a call from the Service Dept. that the oil looked "milky" and there was "moisture" in the engine. Now, if this were a water-cooled engine, it would typically indicate a leaking head gasket that allowed coolant into the crankcase. But, of course water into the engine isn't possible with an air-cooled engine. Oil has been changed regularly. Last oil change was 11 months and 1700 miles ago with Castrol Euro Synthetic 5/40 at the shop many of us use for our Porsche's, BMW's and Mercedes.
My question is this: What do you RLers think may have caused this? Just 4 days ago we did a 200 mile round-trip on the highway. That should have cooked off any moisture from sitting in a not yet air conditioned garage too long in the heat and humidity of south Florida.
Your help will be appreciated.
02-16-2017, 09:20 AM
#3
Racer
Thread Starter
02-16-2017, 09:47 AM
#4
RL Community Team
Rennlist Member
Rennlist Member
I believe the cause is combustion fumes that make their way into the crank case, as a normal byproduct of a running engine, contain water. I have seen this as a milky residue on my 86" Carrera under the oil filler cap. I suspect getting the engine hot cooks off a lot of this moisture but once the foam is stuck to the oil filler cap I am not sure if the cap gets hot enough to evaporate the moisture component.
Andy
Andy
02-16-2017, 09:54 AM
#5
Well Porsche themselves does not recommend that light an oil for a 993 anywhere near your (likely) normal running temperatures. Also, look up ZDDP used as an additive on our flat tappet engines and find out how important it is....and how few modern oils have adequate levels for our engines. As for the milkiness, it seems that the duration of your trips do not dry out the condensation formed in your high humidity environment. Probably an analysis is the way to go. Cheers
02-16-2017, 10:52 AM
#6
Well Porsche themselves does not recommend that light an oil for a 993 anywhere near your (likely) normal running temperatures. Also, look up ZDDP used as an additive on our flat tappet engines and find out how important it is....and how few modern oils have adequate levels for our engines. As for the milkiness, it seems that the duration of your trips do not dry out the condensation formed in your high humidity environment. Probably an analysis is the way to go. Cheers
02-16-2017, 11:23 AM
#7
RL Community Team
Rennlist Member
Rennlist Member
Trending Topics
02-16-2017, 11:48 AM
#8
Rennlist Member
02-16-2017, 12:13 PM
#9
Rennlist Member
Sounds like it's just atmospheric water condensation in the sump that occurs when you have a temperature differential with a warm engine that is run for very short intervals and then left in a cold environment overnight. Usually not an issue if it's a small amount of moisture, you just need to run the engine for extended period of time to get the oil to ~200 degrees (F) to dissipate the moisture.
02-16-2017, 12:15 PM
#10
Rennlist Member
Join Date: Nov 2010
Location: Central California
Posts: 3,484
Likes: 0
Received 12 Likes
on
11 Posts
I may be wrong, but I don't think the CAFE had even instituted 0/20, 5/20, 5/30 oils back in the mid to late 90s. At the very least, they were new to the market. Wouldn't that be a clue that these oils should NOT be used in AC engines?
02-16-2017, 12:19 PM
#11
02-16-2017, 12:53 PM
#12
What everyone said... except the oil weight recommendation's.
What I've found when you get white milky residue is two things that cause that and your shop should tell you the same.
1. Either two oils are being mixed...most common maybe when they do the
oil change they are not draining it all the way for some reason.
2. Your starting the engine a lot and not driving it more than 20 mins to
burn off the condensation. The worst thing you can do is start it, let it idle
for a while and move the car around then shut it off.
It sounds like you caught it early. It's not a big deal, change the oil and filters. What I would do is put a bottle of Marvels Mystery Oil in just once and that will clean up any residue inside. and leave it in until the next oil change.
I would focus on when you start the car to drive it at least 20 mins. Storing it has nothing to do with condensation in the oil.
Your A/C problem sounds like a bad temp sensor in the CCU, climate control unit. The dealer will be able to pull codes with there hammer tool and know exactly what is wrong. Could also be a bad resistor on the rear engine fan.
Valve covers, especially the lower covers are very communion to leak. So is the timing case cover.
What I've found when you get white milky residue is two things that cause that and your shop should tell you the same.
1. Either two oils are being mixed...most common maybe when they do the
oil change they are not draining it all the way for some reason.
2. Your starting the engine a lot and not driving it more than 20 mins to
burn off the condensation. The worst thing you can do is start it, let it idle
for a while and move the car around then shut it off.
It sounds like you caught it early. It's not a big deal, change the oil and filters. What I would do is put a bottle of Marvels Mystery Oil in just once and that will clean up any residue inside. and leave it in until the next oil change.
I would focus on when you start the car to drive it at least 20 mins. Storing it has nothing to do with condensation in the oil.
Your A/C problem sounds like a bad temp sensor in the CCU, climate control unit. The dealer will be able to pull codes with there hammer tool and know exactly what is wrong. Could also be a bad resistor on the rear engine fan.
Valve covers, especially the lower covers are very communion to leak. So is the timing case cover.
02-16-2017, 01:39 PM
#13
Pro
02-16-2017, 02:31 PM
#15
Hopefully that second statemen was with tongue in cheek! 
Not a good "going forward" idea. 
...But feel free to spend your money on whatever oil you think is best...There is only about a billion oil threads from the not so distant past.
Yes. this is what I am going to use going forward. Porsche developed the formula "in house" specifically for our engines.
...But feel free to spend your money on whatever oil you think is best...There is only about a billion oil threads from the not so distant past.