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New Cat. Converter Vs New used car

My 2003 Honda CRV with 182,383 miles on it 0needs a new Cat. Converter. A 2,600 dolor endeavor. Would investing in it now be wise? Will it give me another 100,000 miles(?) or only 20,000? Or should I put that money towards a new(used) 2008-2010 car?

I would buy a quality after market cat, not a dealer installed cat. The price is way too high.

I had an after market Cat Converter and tail pipe installed on a 98 GMC Sonoma for less than $500.00 Here in Oklahoma a vehicle older than 10 years can operate without a Cat, the Check engine light just will not turn off.

With that many miles on the engine, you need to figure out if the cat died because of age, or if the there’s a problem with the engine that caused damage to the cat.

Because if you install a new cat, but there’s still a problem with the engine, it’s throwing money down the hole.


Like @Tester said, how are you sure it’s the cat, or just the cat? Have you replaced the oxygen sensor(s)? What OBD II code is it? What state do you live in?

+1 to knfenmore’s post.

And who’s to say the “new” used car won’t have even more expensive problems than a tired cat converter?

As to how many miles you’ll get out of the new cat converter, nobody could guess without evaluating the condition of the engine and doing a combustion analysis on the exhaust. The main reason catalytic converters become ineffective is because the catalyst becomes coated with exhaust byproducts. Without knowing how much oil you’re using and what the exhaust is carrying, it’s impossible to guess.

Thank you all! I have not replaced the O2 Sensor yet. I think that should be my first try? I don’t know the OBD II code, but I was told (when I got my oil changed and the nice guy hooked the checky box thing (for lack of what it’s called, sorry) up to check it) that it was the O2 sensor (1).

The when I took it to my dealer ship (super expensive. If I have to get something fixed I’ll take it somewhere else from now on) They told me it was the Cat, O2 Sensor, gaskets, and exhaust pipe that needs to be replaced (along with another 2,000 worth of things that need to fixed) so I’m feeling like they want to rip me off? Any way, I’m Texas but the car is registered in Alabama (still under my dads name)

You might get another 100k miles out of it if well maintained, so don’t give up on it.

Have the oxygen sensor(s) replaced with genuine Honda parts. Aftermarket sensors aren’t always reliable. If that eliminates the codes, you do not need a new cat.

Have this done by a recommended independent mechanic. The dealer will try to sell you unnecessary work.

Have the oxygen sensor(s) replaced with genuine Honda parts. Aftermarket sensors aren't always reliable.

Honda doesn’t make O2 sensors. They are made for them by either Denso or NGK. You can buy Denso or NGK sensors on-line or from a good auto-parts store for a lot less then dealer. And you shouldn’t replace the sensors unless they are needed.

There are tests a good mechanic can preform to determine if it’s a CAT or O2 sensor. Don’t start replacing parts needlessly.

Do you live in an area that has emission testing?

sounds like the dealer is trying to milk you like a cash cow

Regarding those oxygen sensors . . .

I’m well aware that Honda doesn’t actually make the sensors

That said, the sensors that get packaged in the Honda box sometimes undergo more rigorous testing than those that are sold in the Denso box

Over the years, I’ve had some bad luck with parts that were made by the OEM, but weren’t sold in the Toyota, Honda, etc. box

I’ve had less bad experiences when buying things directly from the dealer

It is definitely a judgement call

There’s something else to consider. The dealer sensor will have the Honda part number AND the Denso part number on the part. Whereas the aftermarket sensor will only have the Denso number on the part.

I’m assuming this all started when the check engine light came on, not b/c of an emissions test failure. There are probably two O2 sensors involved, one before the cat and one after. The engine computer monitors both. The readings will track each other in a known way if the cat is working properly. Presumably the readings are not tracking correctly, and that turned on the CEL. But you don’t know at this point whether its the cat or the O2 sensors that are misbehaving.

The problem is that while there are tests for both cats and O2 sensors, the tests are not always definitive. O2 sensors can be inexpensive enough it can make sense $$-wise just to replace them if they are suspect. I paid $50 for a Denso O2 sensor for my Corolla a couple weeks ago.

If the shop has an emissions tester, that is a pretty good way to determine if the cat remains functional. There’s also a “back-pressure” test that can tell if a cat is bad, but doesn’t necessarily confirm it is good. That test is done by removing the O2 sensor. So you might ask your shop if they are able to do an emissions test at the tailpipe, and to ask them if it makes sense a back pressure cat test be done at the same time the O2 sensors are replaced.

BTW, I was pricing Calif-accepted aftermarket cats for my Corolla the other day and saw some online (at RockAuto) for $200-$250 each.

@db4690‌, do the Denso part numbers on the OEM and Honda/Toyota boxes match? If so, it seems like the parts would be identical. I know that auto manufacturers provide a detailed purchase specification. If Denso uses the same part number on the Honda box and their own box, it implies strongly that they manufactured their own brand parts to the same spec that Honda provided.

If you go to Advance Auto, they have the correct sensor for your car. They will lend you the tools too, if you’re up to it. Or go back to the guys you started with. I changed out mine last fall 2004 CRV-EX 98K miles. Some times you can find an honest Honda service mostly you can’t. :frowning:

This all very helpful! I’m going to try changing the O2 sensor first and get an emissions test done. I found a place (Rusty’s muffler) I’ve been told is good and won’t scam me. He said I just need to bring him the sensor and he will change it. I’ll go to Advance Auto for it! I really appreciate all the advice.


I can’t speak with certainty about Honda . . . but this is how Mercedes-Benz does it

Parts that pass their own tests get the Benz part number stamped right on the part, in addition to the Bosch, Temic, etc. part number. And they are packaged in a Benz box.

Parts that do not pass their own tests don’t receive the Benz number. They have only the Bosch number, for example, and nothing else. And they do NOT get packed in a Benz box

So, to sum it up . . . the genuine Benz parts passed 2 tests, whereas the Bosch parts only passed one test

I know I’m being a nitpick, but the Denso part and the Honda part are not technically identical

Paying for dealer parts is not a total ripoff, in my opinion

That makes sense. I was thinking that if Denso packaged both the Denso brand and Honda brand parts they would have to be identical if the Denso part number is the same on both boxes. Your explanation shows the difference. Thanks.

It’s actually sort of a mix. In some parts, for some customers, special testing is performed in addition to the basic functional tests. In many mass produced parts, especially generic parts, the car manufacturer gets exactly the same parts as the parts store, only with a different logo and part number on the side. In some cases the car manufacturer requires that only their name and part number be on the parts (and boxes), and in others the part manufacturers name and part number are also there.

With Denso parts, you can feel confident that the part will be the same as the car manufacturer’s, but when in doubt it generally makes sense to get the part from the car dealer. Especially if the cost of replacement is largely labor. But always ask nicely if there’s any discount they can give you. They will almost always give you one.

Speaking of Denso parts . . .

A few months ago, I bought a Denso oxygen sensor for a Toyota. It plugged in okay and did the job, but the wiring was so long, that I had to use a lot of zip ties to keep it from interfering with other components