Any Car People in the House?

[C_Miller]

Hey. I've been having some problems with my car. It sounded like a lawn mower and got louder with speed. I still was able to maintain my speed though, it was just rather loud. When I went to drive it to the mechanic, there was a rattle under my car. I saw that one of the exhaust pipes was dragging on the ground. So I get it to the mechanic and he told me that my catalytic converter needed to be replaced.

I checked some of the "symptoms" of the need for a replacement and I'm not entirely convinced. One of the things is an oder that the exhaust constantly has. I have never smelled anything. Another one was a major loss in gas mileage. I just did a calculation of my last trip without a fill up and conservative estimates show that my gas milage is well where it should be. Another big one is that the car doesn't perform as well. Since I've been having issues, I haven't really tested the performance, but what little I did drive, I didn't notice any drop in performance. And I have yet to find catalytic converter problems spell out my symptoms.

I'm skeptical. It's an expensive problem and I don't have them money if it's not something that actually needs to be done. So I was wondering if anyone could help out. I know you can't really diagnose it without seeing it, but just tell me if there is cause for concern.

Thanks!

 

[Robert Maxwell]

A bad O2 sensor will wreck your catalytic converter. A bad cat will cause a lot of rattling and loss of power. You should probably get both replaced.

If you replace the catalytic converter without replacing the O2 sensor, you will probably have another ruined converter in 6 months or so.

 

[Finn]

What happened to my post??? This isn't the first time a post of mine disappeared.

 

[Lindley]

A bad cat will cause a lot of rattling and loss of power.

A bad dog will cause stinkiness.

 

[ares93]

A bad O2 sensor will wreck your catalytic converter. A bad cat will cause a lot of rattling and loss of power. You should probably get both replaced.

If you replace the catalytic converter without replacing the O2 sensor, you will probably have another ruined converter in 6 months or so.

This is the most probable explanation.

However if the engine runs smoothly, meaning th co2 sensor is still alive and kicking, you can simply reseat the exhaust. Aside from shitty co2 levels the car shound run fine. Even with a shot cat. I've been running a jetta with 2" straight pipes from the block. Cats are overrated

Btw i'm a volvo and UNG-20 (race) mechanic.

 

[RAMA]

You mean like in a van down by the river?

 

[ares93]

You mean like in a van down by the river?

Say again?

 

[propita]

I know little about cars, aside from problems I've had. The second you mentioned "smell," I thought catlytic converter. A problem with it gave my car a sulfurous (rotten eggs) smell. The O2 sensor was mostly fine, but damaged and replaced as part of the work. Another time, another car, the O2 sensor was bad but the car seemed to run fine, at least it felt fine. But the exhaust color was bad and the mileage wasn't great.

 

[Finn]

^he said no odor

 

[Gil T.Azell]

What year and make?

 

[propita]

^he said no odor

You’re right. He described that as a symptom which his car does NOT have. I misread that.

A sulfur smell is a giveaway for catalytic converter issues. O2 sensor problems don’t always cause an odor on their own.

 

[Lindley]

A sulfur smell is a giveaway for catalytic converter issues.

It can also indicate a battery problem.

 

[ares93]

O2 sensor failure also causes uneven idling and turbo problems on certain cars. Mostly with Volvo and Saab's light pressure turbos.

The make an model would help a lot. Every cars responds differently to certain part failures. For instance, a shot turbo on my team's 205 Mi16 prevented me from even driving back to the pit. While my father could not only drive his Saab home, but keep a speed of roughly 55mph for over thirty miles.