check valves, where are they located?
Thread Starter
Teching In
Joined: Dec 2004
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check valves, where are they located? I have a 98 LS1 and my air pump is making noise after I start up, but is running great. The dealer said that I could change the check valves, but may not change the whine noise that is present. Is it hard to change the check valves? Can someone point me to where they are located? A picture would be helpful. Thanks. Also, would an aftermarket exhaust have anything to do with the whine noise?
TECH Veteran
Joined: Aug 2002
Posts: 4,055
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From: Hartsdale, NY
The two check valves are located on the pipes that draw vacuume from each header pipe (flange) as gases are forced out the exhaust. They are small black tin can devices with threads about 1.5 inches in diameter. As I recall from memory, I think they are on top of the valve covers toward the back of the engine.....
When headers are installed too much vacuume is drawn by the exhasut and the exhaust check valves flutter eventially burning out - usually within a month or two after install. To cure this problem a metal gasket (block off ) is placed between the header flange and the connecting air pipe. A small hole - like 5/16 - is drilled into the block off late to allow a small amount of vacuume to effect the system...
When headers are installed too much vacuume is drawn by the exhasut and the exhaust check valves flutter eventially burning out - usually within a month or two after install. To cure this problem a metal gasket (block off ) is placed between the header flange and the connecting air pipe. A small hole - like 5/16 - is drilled into the block off late to allow a small amount of vacuume to effect the system...
Hello,
The check valves are the round valves at the end of the air tubes that come off the exhaust manifolds.
The GM part # is 22048212 for both sides. Price is $ 25.89 retail.
Someone may post up how to check them for proper working order.
Hope this helps.
EDIT: beat me to it
The check valves are the round valves at the end of the air tubes that come off the exhaust manifolds.
The GM part # is 22048212 for both sides. Price is $ 25.89 retail.
Someone may post up how to check them for proper working order.
Hope this helps.
EDIT: beat me to it
Launching!
Joined: Aug 2002
Posts: 231
Likes: 0
From: Ontario, Canada
Unless you have roadside blitzes like we do up here. When they haul your car off the road or fine you hundreds of dollars it royally sucks. 
I wish I could ditch that stuff. My EGR pump is SO UGLY!
I wish I could ditch that stuff. My EGR pump is SO UGLY!
TECH Senior Member
Joined: Dec 2001
Posts: 5,399
Likes: 3
From: Jacksonville, FL
The check valves? They unscrew from the metal side of the air tube, use two large crescent wrenches. If you're having trouble breaking them free while on the car remove the clamp and hose, then unbolt the metal air pipe from the header - that way you can put them in a vise or on a bench to get some leverage. There's a gasket between the metal tube and the header, not needed unless you mess one up removing it - if you do they're cheap and easy to replace later - PN 12553617.
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From: Schiller Park, ILL Member: #317
Originally Posted by koolaidkidd
I have a 98 LS1 and my air pump is making noise after I start up, but is running great. The dealer said that I could change the check valves, but may not change the whine noise that is present.
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