Need advice on 98 Corolla exhast repair...

Exhaust leak somewhere in the front. I raised the car on jack stands, crawled under but could not see the problem. I "assume" it is either the manifold or the curved section of pipe attached to the manifold. This section of pipe has a heat shield over it so I cant see it. Well after a weekend of wrestling with the connections I removed both sensors and disconnected the front pipe from the manifold. I was hoping to be able to spin the whole thing out from under the car. no luck.

Looks like I have to separate the muffler from the middle pipe (have to use a dremil to cut the bolts.) This will allow the center pipe section to come out.

QUESTION: In front of the cat. there was a type of clamp. after I cut it off I could see a raised seam. Unfortunately it looks like it is a permanent connection not meant to come apart? The clamp was there to help keep it from coming apart??? If this joint had come apart I could get the pipe and muffler out as one piece. It looks like there are only 3 sections to the exhaust. The muffler (and tail pipe), the middle pipe which has the cat in it and the manifold.... If I am correct and the leak is under the heat shield on the middle pipe just before it connects to the manifold it looks like I will have to replace the whole middle pipe including the cat??$$$$$

I've never seen this type of setup, usually the cat is connected to pipes that could be replaced without doing the whole thing. Also new to me was the connection to the manifold is spring mounted... One side I got out no problem but the other bolt could not be reached because of the O2 sensor. when I tried to remove the sensor it was blocked by the length of the bolt with the spring on it.. I ended up cutting the spring with a dremil. this allowed things to move so I could slide the O2 sensor out and get at the bolt from under the car.... Hopefully I can find a replacement spring when its time to reassemble??? It may be part of the replacement???

Other than being load the pipes I have been able to examine all seem pretty solid. If I remove the heat shield on the front bend of the middle pipe and don't fine a problem I'll have to look at the manifold a little closer or remove it..

Any advice, comments or suggestions would be greatly appreciated..

TIA

SR

Reply to
Steve
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To find an exhaust leak, have someone with work gloves wad up a rag and try to block off the tailpipe while the engine is idling. The exhaust leak will become a little louder, making it a little easier to find. The other method is to use a leak detector to find the leak.

I highly recommend that you identify the actual source of the leak before cutting stuff apart.

Toyota exhausts use flanges to join sections. With this design, all you have to do is cut off any rusted bolts on the flanges to take a section apart. There are no pieces that fit within each other like the tube on a vacuum cleaner and there are no clamps. There are bent rods welded to the exhaust pipe that fit into the exhaust hangers.

On a vehicle with a transverse-mounted engine like the Corolla, the engine will rock fore-aft instead of side-to-side like a longitudinally mounted engine does. Because of this, there has to be a way for the exhaust pipe to flex so it doesn't break off. Two ways to do this are the spring mount where the pipe joins the manifold and a flexible section of exhaust pipe. The areas where the pipe flexes are common sources of exhaust leaks.

Reply to
Ray O

Should have done this first but to late...Although I did narrow it down to the manifold or the flexable joint area...just by listening from above and below. Didnt think to block the muffler to increase the sound...

Two ways to do this are the spring mount

This joint sounds like where the leak is coming from... this area of the pipe in wrapped in a heat shield so until I get it out I cant tell if the pipe under is bad. Or it could be the joint itself is not sealing properly.

On our 93 corolla there was a flexible section of pipe, on the 98 it appears to be a flexible joint where there are springs holding the joint together. Again I have to get it apart to see what it looks like but is seems like ant flexing and the joint would leak???

Stop to pick up some more dremil cut off blades tonight and I'll separate the muffler and then I can pull everything out except the manifold and inspect it.

Reply to
Steve

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