LS1 Air leak behind TB.... is this normal??????

**T/AKing** · 11-21-2006, 10:44 AM

ive been hearing this kind of small wooshing/ sucking from my engine bay for a while but the car drives find so i figured it was nothing. i was tryin to find where the noise was coming from again today and i think i found it. right behind the throttle body theres a big tube that comes out, after about 1 inch it is pinched slightly and then it goes back to normal size and goes next to teh fuel rails to the back of the engine. its right in the middle of this picture. is something wrong wit my car or is this just me not knowing enough about my engine???? lol

**Y2KPewterSS** · 11-21-2006, 01:01 PM

Are you talking about the tube that bolts directly to the top of the intake manifold and has the wire mesh sleeving around it? If thats what you are talking about, that is the EGR tube. Doesn't sound like anything is wrong, I would make sure the one bolt that holds it down on top of the intake is snug though, that could be where you are hearing the leak sound from.

**99_natural_beauty** · 11-21-2006, 01:30 PM

It's normal for that tube to be pinched a little, at least mine is. I also had an air leak behind the TB, mine showed up after I took the stock one out and put in one that was ported/polished. Put the stocker back in and poof it's gone. I also replaced that gasket on both of them a few times, so I don't think it was the gasket not sealing. Only thing I can figure is maybe when the other was polished it caused the back to not be totally level. Jury's still out on that one.

By the way, that tube is for your EGR system. If you've ever taken that tube off or taken the TB off, the gasket underneath the tube could have gotten messed up somehow, or it might just be time to replace it anyway. If the leak is right where that tube is, that's probably all it is, just replace the gasket.

**YoMommasTA** · 11-21-2006, 03:10 PM

thats the pcv hose,its ruined from age and oil.replace it with a piece of 3/8 fuel hose.

**mr.yellow** · 11-21-2006, 05:05 PM

Can't see the pinch. You should just try replacing the pvc hose like YomommasTa said and see if that helps. Pvc is pretty cheap but make sure you get the non collapsable type.

**T/AKing** · 11-21-2006, 06:39 PM

yomomma do i need to replace the entire hose or just that part that has the crimp in it?? any suggestions where to find it?

BTW i changed the pic so it makes a lil more sense thx

**YoMommasTA** · 11-21-2006, 06:48 PM

all you need is a short piece,pull that old piece off from the manifold to the pcv valve,take it to any auto store and get a piece of 3/8 fuel-emssions hose.Cut it to the same length and put it back in place.I'll bet there is a hole in that hose right where you see that pinch.ALSO carefully check the other rubber lines connectors on that system towrads the bk of the engine.Some of todays oils eat at the hoses over time.Its very common,no big deal.

**T/AKing** · 11-22-2006, 09:24 PM

aight. i patched up the hole temporarily n now it gets interesting. lol now the car idles much lower at around 500rpm compared to the 750 before. and mayb its just me but it seems like the oil pressure is running a little higher tho idk y.
n yea its right under the pinch. sorry for bein a pain in teh A but r u sayin just replace the part with teh pinch or the entire tube that goes from the front to back of the intake?? thx for the help

**YoMommasTA** · 11-22-2006, 09:31 PM

just the short pieces of hose.Not the plastic tubing,you will see what i mean once you remove the hose.

**T/AKing** · 11-24-2006, 09:13 PM

aight i should be pickin it up tomorrow. anyone know how the pcv effects the engine??? just cuz when i patched up the hole so it was sealed, the engine idled at about 250 rpms less than it did before (500 compared to 750 ish) and the oil pressure seems to consistently run at a few higher psi than before.