boost leak through valve covers???
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Junior User
Joined: Aug 2014
Posts: 71
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boost leak through valve covers???
So I just put billowed up pipes and changed the broken O ring in the turbo housing. Put everything back together and checked for a boost leak with the home made tester. Boots and everything ARE OK. I can hear air escaping from what seems to be the valve cover or intake. I realize that I am charging my crank case as well but it still concerns me that air is escaping from somewhere besides the CCV. I read the following forum and this guy had the same issue and after he found out he was charging his crank case he was nolonger worried. . . . . Well I am. Sorry for the wordy post. 
Heres the link to the other forum:
Boost leak through valve cover - PowerStrokeNation : Ford Powerstroke Diesel Forum
Heres the link to the other forum:
Boost leak through valve cover - PowerStrokeNation : Ford Powerstroke Diesel Forum
Laughing Gas
Joined: Nov 2013
Posts: 868
Likes: 1
From: SoCal
On a cold engine the piston ring gaps are approx 0.020". Every cylinder that has an intake valve open is gonna let air into the crank case. Crank case pressure will vent out through the valve covers.
Postmaster
Joined: Apr 2012
Posts: 2,613
Likes: 8
From: North Georgia
no way is an engine that will hold 350+psi compression going to bleed down that much pressure from a boost leak test. if he is putting the adapter in the right place... there should be miniscule bleed down through the block.
Op ... to demonstrate the plausibility try spinning your motor over for a few ticks to get your cylinders nice and squirted. that should eliminate .020x8x what like .010-020x.125ish?
miniscule. ring gap, piston to cylinder wall, ring width. x8.
Op ... to demonstrate the plausibility try spinning your motor over for a few ticks to get your cylinders nice and squirted. that should eliminate .020x8x what like .010-020x.125ish?
miniscule. ring gap, piston to cylinder wall, ring width. x8.
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Junior User
Joined: Aug 2014
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truck runs like a champ and dosent burn any oil. . . Im putting the tester where the air filter is therefore charging the block through the CCV. So no im not putting it in the right place. But still I was concerned that crank case pressure was audiable through the VC. Makes me wonder if ive got a leaky VC gasket.
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Mountain Pass
Joined: Feb 2004
Posts: 212
Likes: 11
From: Fallon, NV
Maybe I'm confused but when I hook the Dieselsite Tester up and follow the instructions given by Dieselsite I do get some airflow out the 90 degree hose on the doghouse. Intructions are clear to pressurize intake to 10-15 psi on the tester air gage, shut-off airflow using the ball valve on tester and check for leaks. It does say that the pressure will bleed down through the valves in 30 - 45 seconds. I start to get airflow out the CCV tube at as low as 7 psi? The air coming out smells like crankcase oil . Is air coming out the CCV hookup hose normal. Here's two pictures of my hookup.
Laughing Gas
Joined: Nov 2013
Posts: 868
Likes: 1
From: SoCal
Some air is normal, too much isn't. For reference, iirc, I think mine took between 10-15 seconds to bleed off 20psi once I shut the ball valve.
Any pressure differential from either side of the piston rings will bleed past them whether is 1psi, or 1000psi.
Any pressure differential from either side of the piston rings will bleed past them whether is 1psi, or 1000psi.
