What are the 996 oil separator problems?
Discussion
Cheers great discussion. Re testing the integrity if the diaphragm, if the internal construction of the device is that manifold vacuum is the controlling factor upon the crankcase pressure, and the manifold vacuum is delivered by one or both of those two small pipes going in, surely a good test would be to pull off one or both of these pipes then test for leaks here? Engine off of course. Am thinking simply sucking myself somehow on it to see if it leaks - obviously need to be able do this without getting a mouthful of black stuff! I did a similar test once on the vacuum reservoir using the small bore pipe at the tank vent valve - was ok. I guess this hinges on how the device works but potentially it could be a way of finding the early or minor failures.
Found a discussion that advances somewhat the testing question....
Porsche Engine Oil/Air Separators 101
The Engine oil air separator directly affects the engine crankcase atmosphere because basically all Porsches from 1980 on including the current 986-987-996-997-Caymen & Cayenne engines all are positive crankcase type systems meaning the engine crankcase has vacuum supplied from the intake manifold to collect and burn the residual combustion by-products or blow-by in the crankcase by running it through the engine again, basically to lower the overall vehicle emissions.
On most occasions, when the oil separator fails, intake vacuum in the engine crankcase rises to an unusually high or abnormally high figure and more likely than not ends up drawing engine oil into the intake system usually fouling spark plugs and even possibly causing damage to the oxygen sensors (O2), catalytic convertors and even possibly various other sensitive fuel injection components.
Interestingly enough, the only way to test the oil separator is to periodically test the engine crankcase vacuum with a water filled Monometer AKA an ultrasensitive vacuum gauge. On BMW’s and Porsche’s, the engine crankcase vacuum is normally around 4-7” (Inches) of water. When these oil separators fail the crankcase vacuum can rise to 9-12” and even higher depending on the extent of the failure.
When the oil separator is starting to fail on Boxsters (986-987), generally you will start to see a substantial amount of smoke from the exhaust tailpipe. When the oil separator finally fails, the engine exhaust smoke can reach dangerous proportions that almost look like it was manufactured from an anti-mosquito smoke machine. Unusually enough, on the 999-997’s, when the oil separator fails, it hardly ever creates any exhaust tailpipe smoke, almost being like a silent killer or costly surprise.
On another note, it has been known on rare occasions, that when an oil separator fails that it is possible to have a slightly rich running condition that might turn on the check engine light or CEL. The only way to know what is happening is to check the fuel trim numbers on the OBD-II “Freeze Frame” data and crankcase vacuum to see exactly what’s going on, otherwise your just guessing.
Tony Callas
______________
Owner, Callas Rennsport
Phone: 310-370-7038
Located in the Greater Los Angeles Area
http://www.callasrennsport.com
Porsche Engine Oil/Air Separators 101
The Engine oil air separator directly affects the engine crankcase atmosphere because basically all Porsches from 1980 on including the current 986-987-996-997-Caymen & Cayenne engines all are positive crankcase type systems meaning the engine crankcase has vacuum supplied from the intake manifold to collect and burn the residual combustion by-products or blow-by in the crankcase by running it through the engine again, basically to lower the overall vehicle emissions.
On most occasions, when the oil separator fails, intake vacuum in the engine crankcase rises to an unusually high or abnormally high figure and more likely than not ends up drawing engine oil into the intake system usually fouling spark plugs and even possibly causing damage to the oxygen sensors (O2), catalytic convertors and even possibly various other sensitive fuel injection components.
Interestingly enough, the only way to test the oil separator is to periodically test the engine crankcase vacuum with a water filled Monometer AKA an ultrasensitive vacuum gauge. On BMW’s and Porsche’s, the engine crankcase vacuum is normally around 4-7” (Inches) of water. When these oil separators fail the crankcase vacuum can rise to 9-12” and even higher depending on the extent of the failure.
When the oil separator is starting to fail on Boxsters (986-987), generally you will start to see a substantial amount of smoke from the exhaust tailpipe. When the oil separator finally fails, the engine exhaust smoke can reach dangerous proportions that almost look like it was manufactured from an anti-mosquito smoke machine. Unusually enough, on the 999-997’s, when the oil separator fails, it hardly ever creates any exhaust tailpipe smoke, almost being like a silent killer or costly surprise.
On another note, it has been known on rare occasions, that when an oil separator fails that it is possible to have a slightly rich running condition that might turn on the check engine light or CEL. The only way to know what is happening is to check the fuel trim numbers on the OBD-II “Freeze Frame” data and crankcase vacuum to see exactly what’s going on, otherwise your just guessing.
Tony Callas
______________
Owner, Callas Rennsport
Phone: 310-370-7038
Located in the Greater Los Angeles Area
http://www.callasrennsport.com
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