Oil Blowby
03-01-2010, 06:32 PM
#1
Oil Blowby
So I noticed a quarter size amount of oil below the driver's side undertray on the my car (are below where the intake and piping sits). When the car was on the lift, we noticed the HKS air filter (sits in a low position on the HKS gt SC for the G) was covered in oil and there was some dripping. There also was some minor seeping coming from the piping/couplers near the intake/piping.
The only thing that changed recently was that I took my Cosworth plenum off and put back on the oem/md setup. I am running a ARC v2 catch can. There was only a little amount of actual oil in the catch can; the rest was mostly water and vapor.
I did not notice any oil leaking aroung the valve covers. My engine oil is right in the middle of H and L. The oil is clean. Coolant is clean. Fluid levels are good. The car is running fine and strong--no misfiring--no hesitation and no loss of power.
The pcv valve was replaced with a new one in case this was the cause of the blowby. The intake/pipes/maf sensor was cleaned as well. I was told to drive the car for awhile and to monitor oil and check for potential leaks. So far, I have not noticed any signs of leaks, although I have only driven a few hours after pcv replacement.
Has anyone heard of this happening before? I'm hoping it was b/c of a bad pcv valve. Any suggestions/help would be appreciated. thx! btw, about ~24k miles on my 05 g coupe, using Amsoil 5w30.
The only thing that changed recently was that I took my Cosworth plenum off and put back on the oem/md setup. I am running a ARC v2 catch can. There was only a little amount of actual oil in the catch can; the rest was mostly water and vapor.
I did not notice any oil leaking aroung the valve covers. My engine oil is right in the middle of H and L. The oil is clean. Coolant is clean. Fluid levels are good. The car is running fine and strong--no misfiring--no hesitation and no loss of power.
The pcv valve was replaced with a new one in case this was the cause of the blowby. The intake/pipes/maf sensor was cleaned as well. I was told to drive the car for awhile and to monitor oil and check for potential leaks. So far, I have not noticed any signs of leaks, although I have only driven a few hours after pcv replacement.
Has anyone heard of this happening before? I'm hoping it was b/c of a bad pcv valve. Any suggestions/help would be appreciated. thx! btw, about ~24k miles on my 05 g coupe, using Amsoil 5w30.
03-02-2010, 08:24 AM
#4
I originally thought it was supercharger traction oil, and suspected the oil was overfilled when it was "topped off" my last oil change (currently the resevoir is just a tad bit over optimal level. But, the tech told me that the HKS traction oil is green and the oil that was leaking/dripping was yellow. He also said that the small amount of oil in my catch can was the same type that was leaking/dripping--so from this he deduced that the leaking oil was motor oil.
03-02-2010, 10:52 AM
#7
The tech says the crankshaft pressure might be blowing the oil back and eventually goes to the intake tract.
Could you explain a little more why it's not possible for blowby to occur through the supercharger and on to the filter? Thx.
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03-02-2010, 12:39 PM
#8
You mean crankcase pressure? There is no route from the crankcase back to the SC except back through the piston rings, combustion chamber, intake valves, manifold, throttle body, to the charge pipe, which is receiving air from the SC. If pressure was going through the PCV valve to manifold, it would still just get sucked back into the motor and out the exhaust. You have a leaky SC seal if there is oil in the air filter. There is just no other way. Your throttle body should have been filled with oil if it was really going against air flow - highly improbable. If you overfilled, perhaps it will work itself out...
Last edited by rcdash; 03-02-2010 at 12:43 PM.
03-02-2010, 12:41 PM
#9
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I originally thought it was supercharger traction oil, and suspected the oil was overfilled when it was "topped off" my last oil change (currently the resevoir is just a tad bit over optimal level. But, the tech told me that the HKS traction oil is green and the oil that was leaking/dripping was yellow. He also said that the small amount of oil in my catch can was the same type that was leaking/dripping--so from this he deduced that the leaking oil was motor oil.
03-02-2010, 12:44 PM
#10
Per HKS this oil never needs to be changed or even added. If you need to top it off, then it is burning and or leaking somewhere. I have the GT for a 350Z and the filter is higher up in the bay next to the S/C instead of down lower. Never had any blowby, dripping or anything. Just throwing it out there.....good luck.
03-02-2010, 12:46 PM
#11
You mean crankcase pressure? There is no route from the crankcase back to the SC except back through the piston rings, combustion chamber, intake valves, manifold, throttle body, to the charge pipe, which is receiving air from the SC. If pressure was going through the PCV valve to manifold, it would still just get sucked back into the motor and out the exhaust. You have a leaky SC seal if there is oil in the air filter. There is just no other way. Your throttle body should have been filled with oil if it was really going against air flow - highly improbable. If you overfilled, perhaps it will work itself out...
Last edited by jonnylaw; 03-02-2010 at 01:03 PM.
03-02-2010, 08:00 PM
#12
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not exactly true. Per HKS you are supposed to check traction oil levels every other oil change. If it is below the optimal mark, you are supposed to follow the procedure on adding a little more oil. Also, you you change your traction oil every 3 years/36k miles per HKS rep.
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