Exhaust smell inside

[Hondaman4ever]

Hi.

I just purchased a '00 Civic. The car runs really nice and it feels like it has pretty good power (for a used Civic) but I smell like exhaust gas in the cabin especially when I turn on the fan. It's not really bad but I can easily smell it. No sound (of a leak) though. Could this be a leak? What's the fix if it is? O2 sensor not on or anything else.

I appreciate your reply.

 

[Hondaman4ever]

Thanks for the reply, ctag. I think the smell is mostly on the inside but I'm not sure. I have no idea if there's any broken or missing nuts as I've never took a look under the car. I think the best way is to take it to a mechanic to take a look but I was trying to get an idea what this could be.

 

[HeX]

Thanks for the reply, ctag. I think the smell is mostly on the inside but I'm not sure. I have no idea if there's any broken or missing nuts as I've never took a look under the car. I think the best way is to take it to a mechanic to take a look but I was trying to get an idea what this could be.

Well, ctag is on point with his suggestion. You joined a forum for such answers so you might as well do the basic thing to just look. Otherwise, take to a mechanic if you dont act on the answers you requested.

 

[96Coupee]

you could have an open header somewhere that makes its way to the cabin. had this problem on one of my old cars. hopes this helps.

Sent from my SM-G935T using Tapatalk

 

[Hondaman4ever]

Boofoo, it's an SE (I think Special Edition/Canada).

96Coupee, thanks for the reply. Was that hard/costly to fix?
Is it something that I can check myself (my knowledge about cars is so so).

And, if it's not a header problem, do I need to get under the car to check for such leaks ?

Happy New Year.

 

[Hondaman4ever]

Thanks, boofoo. Check Engine Light is not on. I don't have an OBD scanner but I'll be receiving one in a couple of days and I'll do a scan just in case any codes had been cleared by the previous owner.
I'm not sure but wouldn't a cracked manifold cause some noise and loss of power? There is no noise that I can hear or any loss of power that I can feel. In fact the car seems to have more power than previous Civics.

 

[96Coupee]

A cracked exhaust manifold would not cause a power loss, and it may or may not be audible.

yea it will. it will start eating up gas and you will have loss of power. basic engine sir.

Sent from my SM-G935T using Tapatalk

 

[Hondaman4ever]

I'm no mechanic but I thought a cracked exh. manifold would cause power loss and noises but I just hope it's not what my problem is anyway. Looks like I'll have to get it checked out by a mechanic (at a shop) since it's toooooo damn cold out side and there's snow and ice every where and there's no way in hell I can go underneath the car. lol. Unfortunately, my mechanic is out of town for some time.

 

[XpL0d3r]

yea it will. it will start eating up gas and you will have loss of power. basic engine sir.

Sent from my SM-G935T using Tapatalk

Not always, as @boofoo already stated. I had a Y7 motor with a hairline crack on the exhaust manifold behind the heat shield. No power loss, no loss in gas mileage. I could smell it when it was cold but that was really it. Never thought it was much of an issue until I had a buddy ask me what the smell was one morning. He knew a lot about Honda's then, (I think I was 18 then?), and said it was my exhaust. We ended up taking the heat shield off and could see the crack on the exhaust manifold. When I revved the motor, you could hear the sound increase (a little raspy), but only if my head was under the hood.. couldn't hear the difference from within the cabin.

I'm no mechanic but I thought a cracked exh. manifold would cause power loss and noises but I just hope it's not what my problem is anyway. Looks like I'll have to get it checked out by a mechanic (at a shop) since it's toooooo damn cold out side and there's snow and ice every where and there's no way in hell I can go underneath the car. lol. Unfortunately, my mechanic is out of town for some time.

See my reply to 96Coupee, above. It takes 15 seconds to check the manifold if the heat shield is already missing. If you need to remove the heat shield, I think it's two bolts. You can do this with the car on the ground, just pop the hood.

 

[Hondaman4ever]

Thanks for the reply and the info, exploder. I'll try to do that and see if I can find any visible cracks.

 

[XpL0d3r]

Thanks for the reply and the info, exploder. I'll try to do that and see if I can find any visible cracks.

Let us know what you find, if anything

 

[Hondaman4ever]

I removed the cover and found this crack on the manifold. Since I just bought the car, I'm wondering how long this has existed and whether it's already caused damage ( maybe to the valves) or not. As mentioned, the car seems to run fine but the RPM stays high for a few seconds after I put the gear in neutral when coming to a stop but I don't think that's related. Is it?

So this part (the manifold) comes attached to the catalytic converter, right? Any good place that sells this online?

Thanks.

 

[Hondaman4ever]

Thanks for the reply, ctag. I don't think welding is a fix since it only lasts for a short period of time. So I'll have to buy another one but not a Honda one because I'm sure it will be too expensive. I might look for a good one at the junk yard -I know that's not the best thing to do- or order one from Rock Auto.

I've owned many Civics and this is the first one to have a cracked manifold.

 

[Hondaman4ever]

One question, are the exh. manifold and the cat. made to be one piece or can they be separated ( changing the ex. manifold alone)?

Thanks.

 

[Hondaman4ever]

To be honest, I don't know which engine I have but I'll take a look tomorrow. However, I know the headers are attached to the cat -not separate- and my question is whether they can be separated so that I can just change the exh. manifold part instead of having to replace the whole thing.

This is similar to what I have on my car.

 

[Hondaman4ever]

Ok. Thanks again, boofoo.

 

[Chriscivic]

To be honest, I don't know which engine I have but I'll take a look tomorrow. However, I know the headers are attached to the cat -not separate- and my question is whether they can be separated so that I can just change the exh. manifold part instead of having to replace the whole thing.

This is similar to what I have on my car.

Y7's cat is apart of the header and the Y8's the cats are under the car.

I just put a Y8 exhaust on my Y7 motor, it all bolts up fine but the only issue you're going to run into is having to extend the secondary O2 wiring, due to the catalytic converters being in a different place, which in reality it isn't that hard to do.

Generally, The gasket's tend to rot out in between the pipes where the air inlets are, hence the smell of the exhaust fumes in the vehicle. Does the smell continue if you use the recycle air? Monroe muffler (here in the US, idk if you have them where you're located) replaced the gaskets on my sister's civic for 60 bucks.

 

[Hondaman4ever]

Ok. Thanks for the reply and the info, Chriscivic. Yeah I realize now that the cat. comes one piece with the exh. manifold. I think there's a guy who has a similar piece off his Y7 Civic and I think I'm going to buy it. Or, I might even sell this car and get me an EX.

In my case the manifold has a crack as shown in the first pic. The smell isn't actually that bad and once the car is moving it's hardly noticeable if at all, especially if I use REC air.
So, I'm pretty sure it's just the manifold, not a gasket thing. And no, there's no Monroe muffler here and I don't think you can fix anything for $60 here in canada.

 

[Hondaman4ever]

A couple of questions:

Is it worth it to buy a used cat. ? Found one for about $100 (US) off a car with about 120,000 miles. Or should I just buy a new one (Rock auto sells Dorman brand for $160 US)?

Second, does a cracked exh. manifold cause the car to throw an error code or that's not always the case? The OBD scanner didn't come up with any codes.

Thank you.

 

[Hondaman4ever]

Thanks again for the reply, boofoo. Yeah I think the new cat. is no brainer. A used one is likely to crack any time and the difference in price isn't even that much.