GolfGTIforum.co.uk
Model specific boards => Golf mk4 => Topic started by: wolfie1981 on 13 March 2012, 10:10
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just about to do a service and noticed under the (TB) on the front of the engine theres a breather pipe that has split what i want to know is with this split would i lose boost pressure???
any help would be great
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Yeah, you will have a boost leak if its part of the pcv system or any of the tubes coming from the inlet manifold.
These pipes are under that area.
Also another common one is the 90degree plastic elbow from the oil filter housing is prone to crack and will also cause a boost leak.
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SHOULDNT lose boost if PCV Valve is working, but WILL draw in air under vacuum and cause running problems depending how bad the split is. This is only if the split is on the breather side, i.e after the valve, otherwise your precious boost is escaping!
DITCH IT AN FIT A CATCH CAN (second time this morning, hence the capitals :grin:)
I have removed my PCV system, may have some bits if you have a pic/part number if you are intent on replacing.
(http://i997.photobucket.com/albums/af99/Big_Tone_2010/P1020953.jpg)
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MMM thats strange, The pipe I just explained had cracked and broke in half my car went really boggy and wouldnt hold boost atall.
Changed this and it was oright again so I have always thought if the PCV system is leaking it would cause a boost leak?
Maybe im wrong then.. :huh:
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Yeah, you will have a boost leak if its part of the pcv system or any of the tubes coming from the inlet manifold.
These pipes are under that area.
Also another common one is the 90degree plastic elbow from the oil filter housing is prone to crack and will also cause a boost leak.
thats the one!! the 90 degree plastic elbow from the oil filter looks like the person be for me put some tape around it could this cause me to lose boost then some say yes others say no lol i have the agu engine if this helps
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Mine did and I have a boost gauge. So from Experience I say yes.
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"oil filter housing"/ block??? do you mean the one with the o-ring seal that clips in with a c clip?
If you are leaking boost from here then your PCV valve is also passing as this side of that valve should never be under positive pressure, as its the "breather" system, i.e. its technically a vented system, just re-circulated for emissions i think?
Worth replacing valve whilst you work in that area, only cheap from VW, although, saying that, I bought a brand spanker and it still passed a little, so I bought a Norgren one off ebay and piped that in, much better. (.catch can. :grin:)
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Thats the one that broke on me.
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As above, the hose from the crankcase breather does not carry boost, its a breather. If you was losing boost before it is either because your one way valve further up was shot, or the leak was before the one way valve or your car just needed time to adjust to the change in extraction of blow-by (because a leak further down means the crankcase is not ventilated with the assistance of vacuum from the inlet manifold when the throttle body is closed)
It's quite clear it doesn't carry boost because the hose there is not a boost hose I.e multi-layered or reinforced unlike every other boost hose and if you study the schematics it's very apparent. If it was the case that your entire Pcv system carries boost then fitting a open vented catch can would induce a great big boost leak.
Your sump is not carrying boost remember, this is where the oil in the engine is and it is where the blow-by accumulates (the stuff you see collect in the oil catch can) your oil catch can is also not carrying boost either by extension.
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As above, the hose from the crankcase breather does not carry boost, its a breather. If you was losing boost before it is either because your one way valve further up was shot, or the leak was before the one way valve or your car just needed time to adjust to the change in extraction of blow-by (because a leak further down means the crankcase is not ventilated with the assistance of vacuum from the inlet manifold when the throttle body is closed)
It's quite clear it doesn't carry boost because the hose there is not a boost hose I.e multi-layered or reinforced unlike every other boost hose and if you study the schematics it's very apparent. If it was the case that your entire Pcv system carries boost then fitting a open vented catch can would induce a great big boost leak.
Your sump is not carrying boost remember, this is where the oil in the engine is and it is where the blow-by accumulates (the stuff you see collect in the oil catch can) your oil catch can is also not carrying boost either by extension.
:wink:
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Awsome explanation and totally makes sence.
I shall go back under my rock and hide haha
But I would definatly agree with fit a catch can :wink:
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No hiding under rock! :grin: this is a forum and these are meaningful discussions which can only be a good thing! Who's right or wrong is cometely insignificant to anyone reading these threads. I know when I browse forums I look for explanations as to why things are done the way try are and not an online script of East Enders :sick:
I didn't know either when I used to look at the maze of hoses before I was shown the schematics. But it made so much sense after I saw the schematics, it was then you realise what was part of what and which was detrimental whilst which could pretty much be ripped out.
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thanks for all the replys anyone have a pic of a pcv vavle ???
is there a way of testing if mine is on its way out or its shot
ive just installed a new boost gauge as the one i bought was cheap the car seems to run well but i dont think the boost is rite!!
if i give it the beans around 4000rpm in 3rd i just about get 7psi i do notice the boost tailing off from time to time
sorry with all the questions new to the 18t and now i have one i want it running right :smiley:
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thanks for all the replys anyone have a pic of a pcv vavle ???
is there a way of testing if mine is on its way out or its shot
ive just installed a new boost gauge as the one i bought was cheap the car seems to run well but i dont think the boost is rite!!
if i give it the beans around 4000rpm in 3rd i just about get 7psi i do notice the boost tailing off from time to time
sorry with all the questions new to the 18t and now i have one i want it running right :smiley:
PCV valve - under the inlet manifold in the breather pipework, take it out, clean it up and you should only be able to blow air through one way - although VW ones are cack.
7-8 psi ok for standard I think, someone will confirm.
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yes 7psi is what standard car should be :wink:
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thanks for that i was told 8/9 standard boost that was on a diff site and most of them seem to talk sh** lol