Header leak?
Header leak? I started to hear a difference in the car(96 SS) that I think is a header leak. It's pretty much normal sounding at idle when not in gear. But when under load while driving I can hear the phht, phht, phht type noise while accelerating. It's not very noticable while cruising but you can still hear it's not quite smooth like it was before. The long term fuel trim for bank 1 is running about 7-10 higher than bank 2 and the O2 readings for bank 1 will go down as low as 25 sometimes. So does this sound like a header leak on the driver's side header? You just can't hear it while standing next to it and revving the engine and I see no signs of where the leak is. I'm pretty sure I'll be taking a look this weekend but want to make the best guess at which side it's coming from.
Teching In
Joined: Jan 2005
Posts: 47
Likes: 0
From: Michigan
i had a header leak on both of of mine (burnt the gaskets). stick your head by the header and rev the motor with the throttly body, or have someone inside rev it up for you and listen. you should be able to hear the phht phht sound coming from the header.
No, you can't hear the leak when you stand there and rev the motor so it must be a really small leak. I'll probably just try tightening the header bolts again to see if it seals it up but I'm guessing I'll need a new gasket.
Ok, I've been thinking about this again and the long term fuel trims are 7-10 lower on bank 1 during normal cruising conditions. The O2 readings I'm not real confident about. But the fuel trim readings are making me think it's the passenger side that has a leak and is sucking in air during cruise conditions which is causing a lean reading and the computer is dumping more fuel to that side. I'd rather figure out which side is leaking so I don't have to replace both gaskets so if anyone thinks it's the passenger side based on the fuel trim readings let me know.
TECH Apprentice
Joined: Jan 2004
Posts: 315
Likes: 2
You will notice the gas mileage go down if it is a leak. By the reading you are getting with your scan tool I bet it is. I just fixed one on my car. My gas mileage went up exactly 10% after the fix. I could actually see the exauhst with the hood popped open on a cold day coming from the header. I had a loose/lostbolt.
