I am not sure if there are two catalytic converters (CC) in my Honda Civic 2003 EX Coupe. I want to order, but some places also talk about a manifold CC, which others only say I need a under-carriage one. How do I determine if I have two CCs or just one, and if so which one?

Any pointers for this rookie, will help.

Thanks

 

It should only be one cat that is also the exhaust manifold.

 

Not sure what you are saying. I know that there is a catalytic converter under the car (See pic 1 below). Then there is another one that car part sellers sell for the same model (See pic 2). If there is only one, which one is the one I need for me car. Can't get an answer for this anywhere.

 

You need the top picture one. You do only have one catalytic converter. That bottom picture is for Civics the model 7th gen Civics that have a D17A1 (non-VTEC model). Your EX has a D17A2 (VTEC model) engine with the two-part manifold assembly.

 

Thank you, toyomatt84. This is very helpful.

Sharaaz

 

I'm in the process of doing this now with my 2003 EX. Replacing the CAT and the resonator tube. The flange where the two are joined was completely rusted and fell apart last week and there is a hole in the CAT.

I purchased the MagnaFlow cat mid-pipe as it is mandrel bent (the diameter is consistent throughout the entire pipe) like the original but it is stainless and $400.00 USD cheaper; the only caveat is that it is not CARB compliant.

I purchased the OEM resonator as I did not want to replace my muffler and painted it with VHT paint and got all stainless hardware.

Yesterday I removed the resonator and loosened the CAT tube and the two OXY sensors. I recommend using PB-Blaster on the spring bolts for a few hours and do recommend replacing with , as it has a 15 mm head instead of the std 12 mm. I had to to bang on and 11 mm socket in a couple of cases as the 12 mm bolts were rusted down.

All parts (gaskets, MagnaFlow, spring bolts) were sourced from Amazon except the resonator which was purchased from Majestic Honda.

Amazon Shopping list:

• MagnaFlow 93228 Direct Fit Catalytic Converter (Non CARB compliant)
  MagnaFlow 93228 Direct Fit Catalytic Converter (Non CARB compliant)
• I wanted to try two different gaskets you only need one if you are just replacing the CAT
  • Walker 31360 Exhaust Gasket
    Walker 31360 Exhaust Gasket
  • Bosal 256-036 Exhaust Gasket
    Bosal 256-036 Exhaust Gasket
• Walker 31383 Hardware Gasket
  Walker 31383 Hardware Gasket
• Walker 35129 Exhaust Spring Bolt Kit
  Walker 35129 Exhaust Spring Bolt Kit
  (
  • I need two you only need one if you are replacing the CAT
  • I have extra if you need let me know.
• 3/8-Inch Drive by 7/8-Inch (22mm) Offset Oxygen Sensor Socket |ARES 70039| Wire Gate Accesses Sensor from the Side, Preventing Damage to Wires
  3/8-Inch Drive by 7/8-Inch (22mm) Offset Oxygen Sensor Socket |ARES 70039| Wire Gate Accesses Sensor from the Side, Preventing Damage to Wires
  • Highly recommend this as you can apply the necessary torque to remove the OXY sensor without damaging anytyhing
• 3 stainless nuts, washers and bolts for the flange from local hardware store

Cheers,
Dan

 

Finally finished this weekend everything from the mainfold was replaced and painted with VHT silver, except the CAT as it is all stainless.