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does the PCV failed?

kakluote

Ready to race!
Location
beijing
Car(s)
Audi TT K04
hard to plug out oil cap,
after plug it out, loud "zi zi zi" air sounds coming

is this the sign of pcv failure.?
 

tedted

Newbie
Location
CA
do you have a CEL ?
Does your idle change when its off?

I can easily pull my oil cap off and doesnt affect idle.
I thought if the cap was hard to pull off that was good?
 

kakluote

Ready to race!
Location
beijing
Car(s)
Audi TT K04
do you have a CEL ?
Does your idle change when its off?

I can easily pull my oil cap off and doesnt affect idle.
I thought if the cap was hard to pull off that was good?

when cap was off, the idle was rough..
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
The PCV is fine if idle/rev is smooth when idling while something is removed. There should be suction as well.
 
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kakluote

Ready to race!
Location
beijing
Car(s)
Audi TT K04
The PCV is fine if idle/rev smoothness changes while idling and something removed. With the cap off and idling, place your hand over the filler hole and feel/notice suction or no suction....also notice rev change or no change.

So, OP, your PCV should be fine if cap is hard to remove while idling. I used to run a 'PCV plate/constant recycling'...can't remember if it made the results different...? I still have the BSH stage 1 PCV just in case I started going through PCV's over and over. But have yet to have one fail. It's been replaced twice due to open campaigns, but never due to failure.

feel suction and a little bit rough idle after put oil cap off...

someone said shouldnt experience rough idle
 

vegasGTI

Go Kart Champion
Location
Vegas
Take off pcv blow through it. If you can blow through it,it's bad. I stopped replacing them years ago and have a block off plate.
 

tedted

Newbie
Location
CA
1. the cap initially does feel like negative pressure on it but once its off, it feels like pressure coming out with a gurgly chugging sound. with the flashlight on it, I can faintly see smoke or vapor?

2. rpms do NOT fluctuate when the cap is off.

3. what side of the pcv do I blow through? in or out?

now the kicker.. I drained my can last week and literally rusty looking water came out. Usually its always oily looking water with some chunks and always separates in the bottle. This was just mucky looking and no I have ZERO sludge on my oil cap.

I currently have the BSH CC
 

kakluote

Ready to race!
Location
beijing
Car(s)
Audi TT K04
1. the cap initially does feel like negative pressure on it but once its off, it feels like pressure coming out with a gurgly chugging sound. with the flashlight on it, I can faintly see smoke or vapor?

2. rpms do NOT fluctuate when the cap is off.

3. what side of the pcv do I blow through? in or out?

now the kicker.. I drained my can last week and literally rusty looking water came out. Usually its always oily looking water with some chunks and always separates in the bottle. This was just mucky looking and no I have ZERO sludge on my oil cap.

I currently have the BSH CC

i did feel big suction when take.out the oil.cap
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
There should be suction. However, I was incorrect on the idle change...should run smooth if pcv is OK. I apologize for for the incorrect info...went on memory and it gets wrong sometimes...bcuz 55yrs I guess. Will edit the post with correct info :sm3:
Here's some reading...http://mkv-gti.net/wiki/index.php?title=PCV_valve_failure ...although I believe the writer to be incorrect where it's said "The system consists of a rear valve that is attached to the turbo inlet to provide fresh air into the crankcase". I believe the valve inside the rear tube closes to disallow flow from the turbo into the crankcase under vac at idle. I cannot imagine why the rear tube allows intake flow, under vac, when the PCV has an anti-return valve just on the other side of the valve cover...making the pcv to rear tube channel through the valve cover a one-way trip.

VegasGTI is correct in that if you blow where there are anti-return valves...if you look at page 13(page 9 of the document) and notice where the anti-return valves are: http://mkv-gti.net/wiki/images/e/e7/The_2.0L_FSI_Turbocharged_Engine_Design_and_Function_VW20T_.pdf
 
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kakluote

Ready to race!
Location
beijing
Car(s)
Audi TT K04
There should be suction. However, I was incorrect on the idle change...should run smooth if pcv is OK. I apologize for for the incorrect info...went on memory and it gets wrong sometimes...bcuz 55yrs I guess. Will edit the post with correct info :sm3:
Here's some reading...http://mkv-gti.net/wiki/index.php?title=PCV_valve_failure ...although I believe the writer to be incorrect where it's said "The system consists of a rear valve that is attached to the turbo inlet to provide fresh air into the crankcase". I believe the valve inside the rear tube closes to disallow flow from the turbo into the crankcase under vac at idle. I cannot imagine why the rear tube allows intake flow, under vac, when the PCV has an anti-return valve just on the other side of the valve cover...making the pcv to rear tube channel through the valve cover a one-way trip.

VegasGTI is correct in that if you blow where there are anti-return valves...if you look at page 13(page 9 of the document) and notice where the anti-return valves are: http://mkv-gti.net/wiki/images/e/e7/The_2.0L_FSI_Turbocharged_Engine_Design_and_Function_VW20T_.pdf

what is the function of
Pressure
Control Valve in page 9?
i think it also.easy to.damage. how to check ?
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
It's a reroute valve, under vac at idle it is open to the intake mani...under crankcase pressure/boost, it opens to the turbo's inlet port. Go down one page and you'll see where the rear breather connects to the turbo inlet.

how to check ?
Do you see where the diagram shows flow out of the PCV? Those points are where you check to see if you can blow in to them.
 
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tedted

Newbie
Location
CA
ok so blowing through the pcv..

PICTURE FOR REFERENCE***

On the block off plate their are the 2 hoses. I can blow through the left side easily. On the right side it was pretty sealed... unless I blew really hard then I swear I heard a slight gurgle or flop sound coming from the driver side of the engine for a brief second.

EDIT. looking at the pdf and how the arrows flow, the only outlets would be 'intake manifold gas outlet', which on my plate is blocked and the hose going down to oil pump? but I replaced that hose early on during my binge finding for p2177 since their was a lot of oil residue around the wiring harness' in that area. Any reason to believe the gasket on that oil pump could be related to anything?
 
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vegasGTI

Go Kart Champion
Location
Vegas
If you have a catch can it eliminates the pcv return functions and stays open always.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
If you have a catch can it eliminates the pcv return functions and stays open always.
Ted...↑This↑...none of this relates to yours. It is only the oem PCV you can test in this manner to see if the anti return valves are intact inside the PCV. The OP has a stock PCV.
 

kakluote

Ready to race!
Location
beijing
Car(s)
Audi TT K04
just bought a new oem pcv,
doing the oill cap test,big difference
new one : vac cause. big suction, not easy to take suction
for the old pvb ,the suction
 
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