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Replaced PCV Oil separator

cbenjes

Go Kart Newbie
Location
Bel Air, MD
Over the weekend I replaced my 2016 GTI's PCV Oil separator. The car has 97,000 miles and I have read where they can generally fail by 100,000 miles. Simple job, took about 30 minutes. Good, preventative medicine with the cold Maryland weather dead ahead. Interestingly enough, before the replacement, my VDO oil pressure gauge was reading about 27 psi at 2600 rpm on the highway. After replacement, the gauge is reading 40 psi at the same speed. The PCV was the only thing I replaced, so I have the feeling that the old one was beginning to fail. Anyone else have a similar story? Can the PCV system affect oil pressure? For those that have an oil pressure gauge, what does yours read at consistent highway speeds?
 

GTIfan99

Autocross Champion
Location
FL
Not sure, but I'm here for a smart person to chime in.
 

Wastegate13

Autocross Newbie
Location
SoFla
I'm not a smart person, but going to assume the obvious. I'd reckon a part called the "pressure control valve" could absolutely affect oil pressure.
Positive crankcase ventilation is the acronym.

EDIT: not smart enough to know whether it affects oil pressure.
 

Acadia18

Autocross Champion
Location
Rhode Island
Car(s)
2016 GTI SE

scrllock

Drag Racing Champion
Location
MI
Were you comparing that at the same oil temp? We have a 2-stage sump that has a low and high pressure setting depending whether you're over some temp threshold.
 

cbenjes

Go Kart Newbie
Location
Bel Air, MD
Yes, watching oil temperature vs. oil pressure, the gauge is pegged at 90 psi when the oil is bone-cold. As it approaches the upper 100* F mark, the pressure will fall rapidly to around 40 psi at highway speeds. The original post is information for when the oil temps are around 200*. My drive to work is about 50 minutes at 65+ mph on I-95, so there is a lot of time for consistent pressure/temperature readings. As you stated, when the engine exceeds something like 3500 rpm, it kicks into high pressure mode, like when accelerating, and cruising at 2500 rpm, it's now around 40 psi, as opposed to 27 psi with the oil PCV valve.
 

cbenjes

Go Kart Newbie
Location
Bel Air, MD
OK, my final thoughts on this: With the replacement of the original PCV valve at 97,000 miles, I am seeing increased oil pressure measuring right around 40 psi at 207*F oil temperature running at 2500 rpm. Before the replacement, oil pressure was about 27 psi under the same conditions. I guess I have to deduce that the original was failing and had an air leak or something that was decreasing pressure. I think the reason for a lack of similar experiences is that most people wouldn't see this without an oil pressure gauge, and your first indication of a failure or decreased oil pressure would be a warning message or check engine light. Hope this helps someone. More only if anything interesting arises.
 

GTIfan99

Autocross Champion
Location
FL

Acadia18

Autocross Champion
Location
Rhode Island
Car(s)
2016 GTI SE
Yep, took 30 min going slow.

Took 6 hours going fast, because I dropped a triple square into the open engine...

Not really, but I could see that happening :ROFLMAO:
 

seanmcd1

Autocross Newbie
Location
SC
OK, my final thoughts on this: With the replacement of the original PCV valve at 97,000 miles, I am seeing increased oil pressure measuring right around 40 psi at 207*F oil temperature running at 2500 rpm. Before the replacement, oil pressure was about 27 psi under the same conditions. I guess I have to deduce that the original was failing and had an air leak or something that was decreasing pressure. I think the reason for a lack of similar experiences is that most people wouldn't see this without an oil pressure gauge, and your first indication of a failure or decreased oil pressure would be a warning message or check engine light. Hope this helps someone. More only if anything interesting arises.
Can I see your sweet VDO oil pressure gauge setup!?
 
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