Oil in intercooler tubes -- turbos shot?
03-11-2012, 09:17 PM
#16
Nordschleife Master
My advice is to leave the turbos alone. You say it is running great and not smoking. Use a heavier weight oil (15W50 or 20w50) and don't keep overfilling it. Don't add a quart until the dash indicator won't budge off the lowest mark at HOT idle.
03-11-2012, 11:02 PM
#18
Race Car
03-12-2012, 03:32 AM
#20
Drifting
I had a look at mine some time ago and found the same oil.
I ordered new check valves and they are still in the box unused as we speak.
Like what everyone else said, if it aint broke.......................
I ordered new check valves and they are still in the box unused as we speak.
Like what everyone else said, if it aint broke.......................
03-12-2012, 03:45 AM
#21
Addict
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Lifetime Rennlist
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Yeah, I agree. if the car is not smoking, can do 0.8bar in stock trim, and runs well, just drive it. You will know if the turbos go sideways!
03-12-2012, 06:43 AM
#22
Racer
03-12-2012, 06:49 AM
#23
Racer
03-12-2012, 01:16 PM
#24
Nordschleife Master
The reason I ask is I'm having some issues also and wondering what my problem is. Last three times I've driven it I get heavy smoke out of the left turbo on start-up. This is usually after the car sits for a week or more. Smoke clears after a few minutes but definitely not normal. No recent oil change. Don't mean to hi-jack....wondering if I need to trial the check valves. thanks
03-12-2012, 02:55 PM
#25
Racer
Thanks, the last oil change was at a Porsche dealer. Have not checked to see what filters were used. Will do that.
03-13-2012, 05:51 AM
#29
Instructor
I had Turbokraft ones fitted. When I bought my turbo it smoked on occasion, but had been standing in a collection for a couple of years. I suspect the oil had been overfilled as there was some in the intercooler. Since fitting the check valves I've had no sign of smoke on start up or otherwise. So I'm not sure whether the check valves have solved the smoke issue or just use/correct oil filling. Still, I view it as something of an insurance policy - stopping oil getting syphoned back into the turbos has got to be a good thing right? I'm using fully synth 5w40 Havoline Ultra (the basic Ultra, not the Ultra S) oil.
03-13-2012, 09:41 AM
#30
Track Day
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Oil in intercooler or leaking/oil wet turbos:
Several problems related to above symptoms are related to the fact that the turbos are the lowest part of the engine.
The turbos sealings are designed to provide a perfect oil sealing while the shaft is hot and rotating at up to 100000rpm. When the turbo shaft is not rotating and at standstill the sealing is usually not important. I say usually because in most engines the turbo is mounted higher than the oil level in the engine. This is true for most cars, except for Porsche where the turbos are located below the engine oil level. As long as the turbo sealing is working while the shaft is spinning then the turbo is good. Once you start getting blue smoke on the exhaust while the engine is running this could be a sign of a failing shaft seal and soon also the turbo shaft bearing will fail, hence the turbo has to be overhauled.
Please remember that the turbo sealing must only seal while the turbo is spinning.
On the 993 Turbo with its lowpositoned turbos it can happen that oil passes the turbo seals while the engine is shut off. Just by gravity the oil will always try to find its way down! And the lowest place is the turbo! Therefore it can happen that during engine off oil creeps by the turbo seals and gets into the cold or hot air side of the turbo. The hot side is equal to the exhaust, so oil in the exhaust will show as short moment of blue smoke. Oil in the cold side will collect in the intercooler hoses and in part be aspirated and burned. Not all oil that you find in the intercooler comes from the turbos. Oil vapors from the crankcase are by design routed in the intake area to where the intercooler is connected and some oil vapor will condensate and remain the intercooler.
For the 996 Turbo Porsche did change the design and the following was fitted to avoid above scenarios:
1. The Turbo check valves 996 107 030 78 , (90 USD each). These valves are inserted in the turbo pressure oil feed line and these valves do also fit the 993 turbo. It is however necessary to adapt the existing oil feed line or replace the oil feed line with a custom made one. Every shop capable of fabricating brake tubes or hydraulic tubes can fabricate you a line for little money.The purpose of these checkvalves is to avoid that -at engine off- oil continues to flow into the turbcharger via the pressure line just by the syphon-effect. On the 993 Turbo there is also a special oil filter with a pressure valve that serves the same purpose.
2. The turbo scavenging oil return lines have a high loop in it to prevent backflow of the oil from the engine block to the turbo. The lines from the 996 Turbo do not fit the 993 Turbo, but I have fabricated custom lines that will fit the 993 Turbo.
Conclusion: By simply adapting the Porsche solution for the 996 Turbo to the 993 Turbo the infamous oil in intercooler / turbo can be cured. Porsche itself opted for both modifications, check valves and return lines, and actually by applying both modifications to the 993 Turbo you can be sure to be trouble free for the future.
Best regards
Andreas
Several problems related to above symptoms are related to the fact that the turbos are the lowest part of the engine.
The turbos sealings are designed to provide a perfect oil sealing while the shaft is hot and rotating at up to 100000rpm. When the turbo shaft is not rotating and at standstill the sealing is usually not important. I say usually because in most engines the turbo is mounted higher than the oil level in the engine. This is true for most cars, except for Porsche where the turbos are located below the engine oil level. As long as the turbo sealing is working while the shaft is spinning then the turbo is good. Once you start getting blue smoke on the exhaust while the engine is running this could be a sign of a failing shaft seal and soon also the turbo shaft bearing will fail, hence the turbo has to be overhauled.
Please remember that the turbo sealing must only seal while the turbo is spinning.
On the 993 Turbo with its lowpositoned turbos it can happen that oil passes the turbo seals while the engine is shut off. Just by gravity the oil will always try to find its way down! And the lowest place is the turbo! Therefore it can happen that during engine off oil creeps by the turbo seals and gets into the cold or hot air side of the turbo. The hot side is equal to the exhaust, so oil in the exhaust will show as short moment of blue smoke. Oil in the cold side will collect in the intercooler hoses and in part be aspirated and burned. Not all oil that you find in the intercooler comes from the turbos. Oil vapors from the crankcase are by design routed in the intake area to where the intercooler is connected and some oil vapor will condensate and remain the intercooler.
For the 996 Turbo Porsche did change the design and the following was fitted to avoid above scenarios:
1. The Turbo check valves 996 107 030 78 , (90 USD each). These valves are inserted in the turbo pressure oil feed line and these valves do also fit the 993 turbo. It is however necessary to adapt the existing oil feed line or replace the oil feed line with a custom made one. Every shop capable of fabricating brake tubes or hydraulic tubes can fabricate you a line for little money.The purpose of these checkvalves is to avoid that -at engine off- oil continues to flow into the turbcharger via the pressure line just by the syphon-effect. On the 993 Turbo there is also a special oil filter with a pressure valve that serves the same purpose.
2. The turbo scavenging oil return lines have a high loop in it to prevent backflow of the oil from the engine block to the turbo. The lines from the 996 Turbo do not fit the 993 Turbo, but I have fabricated custom lines that will fit the 993 Turbo.
Conclusion: By simply adapting the Porsche solution for the 996 Turbo to the 993 Turbo the infamous oil in intercooler / turbo can be cured. Porsche itself opted for both modifications, check valves and return lines, and actually by applying both modifications to the 993 Turbo you can be sure to be trouble free for the future.
Best regards
Andreas