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As I continue to drive this recently built car, things here and there keep popping up. I just noticed on top of the motor under the throttle body some oil. So I removed the throttle body and see oil on the back side of the throttle body and inside the upper manifold. I'm baffled as to where this can come from because the intake charge pipe is dry.
I have not revved this motor past 3500k rpm because I'm still breaking in the motor. So I don't think it's blow by. The motor now only has about 100 miles on it.
Can someone shed light on what the cause can be? Thanks
It looks like the PCV valve is oriented correctly. Its one-way feature lets crankcase gases flow from the oil filler neck into the intake, but will not let boosted intake air flow back into the filler neck. Sounds strange, but if the valve is working correctly, it WILL allow oil to flow from the filler neck into the intake along with the crankcase gasses.
How did the oil get there? When fresh engine oil was added to the motor, some could have run down the inside of the filler neck and entered the PCV nipple where it opens into the side of the filler neck. It's best to use a long necked funnel that reaches past that nipple to the bottom of the filler neck when adding engine oil so that fresh oil never flows over the PCV valve opening. Also, if the engine is idling when you add oil, intake vacuum can draw the oil in via the PCV line -- another reason to use a long neck funnel for adding oil and shut the damn engine off. Finally, if oil sloshes back up into the filler neck during heavy cornering, etc., it can be drawn into the PCV line and enter the intake.
It looks like the PCV valve is oriented correctly. Its one-way feature lets crankcase gases flow from the oil filler neck into the intake, but will not let boosted intake air flow back into the filler neck. Sounds strange, but if the valve is working correctly, it WILL allow oil to flow from the filler neck into the intake along with the crankcase gasses.
How did the oil get there? When fresh engine oil was added to the motor, some could have run down the inside of the filler neck and entered the PCV nipple where it opens into the side of the filler neck. It's best to use a long necked funnel that reaches past that nipple to the bottom of the filler neck when adding engine oil so that fresh oil never flows over the PCV valve opening. Also, if the engine is idling when you add oil, intake vacuum can draw the oil in via the PCV line -- another reason to use a long neck funnel for adding oil and shut the damn engine off. Finally, if oil sloshes back up into the filler neck during heavy cornering, etc., it can be drawn into the PCV line and enter the intake.
I appreciate the explanation. So I did just change the oil and did use a long funnel with the engine off. Also no hard cornering has taken place since I'm baying the car u til broken in. I'll have to check if the PVC valve is faulty. 🤷
All of that is correct. If there is oil in the pcv line then the suspicion will likely be correct. In addition, if the valve is flowing in both directions then that will introduce some other issues
On your aftermarket filler neck, is the PCV nipple attached up near the cap (as on the stock neck), or is it mounted lower, near the bottom?
Have you checked for oil in any of the other hoses connected to the upper manifold near the PCV line?
So I only have one hose going to the upper intake manifold which is the pvc valve from the top of the oil filler neck. The valve doesn't have an arrow indicating the direction.
I took off the valve an it sounds loose internally when shakened. I believe that's a sign that it's still in working order. I also blew from one direction which went through and from the other direction had resistance.
If it was inside the intake, then how is it also on top of the engine beneath/outside the intake? Did you forget to use a gasket, or not tighten the TB down properly, or …?
The TB was actually very tightly secure. It took quite an effort to loosen the bolts. Could be that the metal gasket has voids. That will most likely be replaced. What I need to figure out is why oil is there in the first place.
If the pcv valve was installed incorrectly would that allow excess oil to pass?
Last edited by coolrotariesR1; 01-19-23 at 03:01 PM.
supposedly for the pcv valve and then into the UIM, but thought I read somewhere there are two(?) nipples on there. If so then somebody more familiar with the OE functions will need to pipe in.
Thanks for the link. I searched endlessly but came up short on the use of the nipple on the center iron.
What do you mean when your referring to the oil sump?
01-18-23, 06:25 PM
