chasing exhaust leaks - replace gaskets?

[rebuild]

Can exhaust leak from the exhaust 'joints' or gaskets? Do you periodically swap them out to keep that from happening? Or they should not be a problem?

Also if the muffler comes off the hangars, is there supposed to be all kinds of play down to the cat? or is the cat supposed to be braced still? (I haven't looked at that closely lately & no lift.)

Can exhaust leak out of the engine compartment and draft into the cabin?

How about entry from rear bumper into trunk?

Can changing O2 sensor/s clean up exhaust any if no check engine light on?

Going up big hills the exhaust in the car can get pretty bad.

Thanks.

[Civic Accord Honda]

bad smells going up big hills? u sure its not the clutch? ive had that issue before and its always the clutch... can u hear exhaust leaking? my 3g had exhaust leaks like crazy and they never got in the cabin.. .and that bitch ran pig rich

[Oldblueaccord]

Im gonna guess its the flex joint got some leaks.

Sometimes on a cool morning when you first start your car you can spot leaks underneath. Otherwise you just need to fell around with you hands which is not easy without a lift.


wp

[Dr_Snooz]

Please stop driving the car until you get this fixed! Carbon monoxide is very unhealthy and causes all kinds of neurological problems at relatively low doses. It sounds like someone has been monkeying with the exhaust system. Did you get the cat replaced recently? There are a number of sealing rings that must be replaced when the exhaust system is taken apart. If you don't replace those, they can leak. Chances are good that when the cat was replaced, the support bracket just in front of it got left off, which is why you notice the extra slop under there. They usually get sawed off and thrown away when a car goes to the yard too, so I had to buy a new one from the dealer.

Anyway, what's the recent history on the car so we can help you a little more?

[rebuild]

No not clutch - I know that smell and that is not nice either. I'll look up the flex joint and see if I can see anything if someone can put it up on a lift (I guess there is an exhaust sniffer tool too - correct?). I've not ever replaced the cat or O2 sensors (have 516k) (should they be replaced?).

You better believe all the windows sunroof go open fast when I smell it. I do have the car kind of gutted: back seats out, carpet out, some trim in the trunk out AND this did happen:
smelled something bad and burning a while ago was my rear bumper being cooked/melted by the tailpipe cause the muffler had slipped out of the hangars and no longer had them to separate the tailpipe from the bumper. So it cooked a U into the bumper the size of the tailpipe. So I put it back in the hangars to get clearance and is ok for a while till wiggles out (have hangars on order).

While I was putting the muffler back I noticed all kinds of play all the way down including the cat which seemed like too much. I do think I saw some kind of bracket from a distance near the cat - if so I wonder how I could reattach that. Think it used to be welded? or bolt on? I will look for it in service manual.

Does the trunk draft air from in the bumper?

Aside from all that, you can still smell exhaust when it is under a load.

Also I have the blower motor out - I don't know if exhaust comes in that hole.

What material are exhaust gaskets made out of? Do they just not do the job after a time and need to be replaced?

[rebuild]

What is a flex joint? I don't show it in my service manual. Is it the curved pipes that connect the exhaust manifold with the cat section?

[Civic Accord Honda]

flex joint is the the part of the pipe that flexs right off of the header


and exhaust can come in from the sides of the bumpers, if the interior is gutted u can see the vents, i would just close them off and see how that does.
and if its leaking exhaust you should be able to see black soot on the pipe where its leaking from

[Civic Accord Honda]

exhuast leak should look like this

thats about how mine looks where my muffler is clamped on to the piping

[rebuild]

You're right - if the exhaust is getting the bumper a little sooty, that should be a telltale sign about a leak elsewhere. That is a nice looking cat bracket I see there - you have to get that from a dealer if it's still getable? Those exhaust piping bolts must be bears to get off if they are all rusty - are they. Just check the side vents in the trunk - just tape them up or tape them from the outside somewhere? Thos vents must be by that dried foamy looking insulation in that rear quarter panel area that you have to get by as you are looking for the sunroof drain tube - right? Is there any other under part for it to come into the car? I can't imaging the gaskets are rubber if they get that hot - but are they?

Thanks. Thanks for the pics too - they help.

I wish I could see an airflow diagram through the whole car & I wonder if I could somehow rig a cabin air filter. (My A/C and heater both smelled bad so I pulled out the blower motor, evaporator and was going for the heater core too but couldn't find the secret lever to push to eject the heater core so I could pull it out and replace it and put the systems back together and have fresh air whether heated or cooled or not.)

[Civic Accord Honda]

the gaskets are metal crush type, the bolts are a cunt to get off almost impossible if rusted...... best to use a nut buster break the nut off drill the old bolt out and install new ones... (its a bitch i know ><)
also the vent is here
behind the top remen box (photo credit goes to labledsk8r)

and the secret eject button to the heater core is 2 10mm nuts on the firewall behind the engine.... there a BITCHHH to get to ><

[labeledsk8r]

you just had to pull up an old pic of my car cah lol

black soot on the rear bumper does not mean you have a leak, means your either running rich or burning oil (or both)

does your car have body rust? sometimes a hole in a floor pan can let in exhuast but really no way to tell untill you get under the car and feel around, if its the stock exhuast still it most likely has rusted out just lightly run your hand down the exhuast pipeing (when its cool) and you should be able to find any rust holes

[rebuild]

I though I had the vents on either side inside the trunk , but only 1 on the driver's side. I tried blocking it from the inside today. How can you just take out two bolts and out comes the heater core? My regular air filter is gone, so maybe they are easier to get to? I thought the WHOLE DASH had to come out to get to it? That's why mine has not come out yet.

[Civic Accord Honda]

the whole dash does have to come out thought u knew that XD i know some people have pulled the whole dash out and still haven't been able to get the heater core out because they didnt know about the 2 bolts on the firewall