EGR tube looks like flexible electrical wire conduit. Follow tube leaving EGR valve on exhaust manifold to underside of intake near throttle body. At the junction of the flextube and a diamond shaped flange that bolts to the intake - that is where it will break.
From: David Cole
Somebody wanted to know if there was a way to prevent to the cracking from happening. i don't think so since i've been told that the original manufacturer of the tube corrugated the entire tube and straightened out the ends where the flanges go. this essentially work hardens the tube right at the flange, and between the thermal expansion and engine vibrations, the tube fatigues off at the flange. at least that's what mine did. i picked up a new tube direct from GM SPO for $55, and it looks like it was made by a different company. Someone also suggested a braze job to fix the EGR tube. I would be cautious about that. EGR gases can get pretty hot (600-700F) and depending on what kind of braze you do, and where it's located, it might be a very temporary fix.
I just replaced my EGR tube about a month ago, and the flange is free to slide on the non-corrugated end of the tube until it meets the stop on the tube end, and is bolted up.
From: Brian
The end that is bolted to the intake is welded to the flange. The end that bolts up to the EGR is not welded to the flange. If the tube is split above the flange at either ends, then you have a problem. Otherwise, when bolted down, the tube should seal properly. Also there are gaskets at both ends.
From: Henry W.T. Luk
"Is the flanged part supposed to be welded/connected to the tube, or loose?"
1985-87 TUBE, EGR valve adapter 10040409 $46.25 1988 ???
The tube on my 1985 was cracked. It was also welded on the ends. The tube on the 1986 engine I bought was not welded and was not cracked. They must of changed the tube on the 1986, as it looked new. Were the 1988 tubes not welded? The newer tubes are a lot better and don't seem to crack as much.
From: Scott Backer
Lots of ways. One is to spray WD40 or carb cleaner at the suspected joint. If engine speed changes due to you spraying this through a crack, you got a leak. Or, find a piece of rubber hose. Hold one end to your ear, one near a suspect location. You will be able to hear the isolated hiss of a leak, depending on the size of the crack.
From: David Cole
I have seen several of these tubes removed, brazed and reinstalled with excellent results. Since all of our cars are outside of 5/50 emissions, this seems a better fix than the approx $80 for the replacement tubes. Every V6 daily driver owner I know has had this tube crack at the throttle body.
From: David Cole
A friend of mine recently aquired a V-6 Fiero with (of course) a cracked EGR tube. Rather than replace it with another Fiero tube (which he couldn't find in a local salvageyard anyway), he scrounged a tube off a 2.8 Fierbird. The bolts on the manifold flange were spaced a bit differently so he used his little grinder and made the bolt holes into slots which allowed the tube to bolt up to the Fiero manifold. The only thing is... the "new" tube doesn't have the little heat blanket. Dunno if that's any real problem or not. Personally, I'd rather have the blanket just because any Fiero people who look under there will know it's not "correct".
From: Al Hunt