Tell me about changing out catalytic converters.

So the wife insisted on taking her new (to her) car to the dealer for an oil change. When she picked it up, they told her it needs a new cat for an estimated $1900. Now I haven’t see the actual quote yet so I don’t know what else us on there. But I see AutoZone has cats for 99 bucks. How hard is it to swap out? I’ve never worked on exhaust before, but I can swap out brakes, alternatives, starters, belts, plugs etc. I assume it’s just a couple of bolts on either end and some gaskets/seals. How likely is it that I’ll need a torch to cut it off (Which I don’t have)? What else?

2010 Honda cr-v
What other info do you need?

Thanks in advance.

You’ll need to spray the bolts with penetrating oil.

Video - of replacing a Honda cat. Its not your exact year and model.

Is your car accelerating ok? A clogged cat will make a car sluggish.

She won’t let me drive it, so I dunno. Thanks for the link and advice tho.

I’m not sure how much a factory replacement costs. I wonder if that shop was replacing the oxygen sensors too?

I’m not seeing enough labor, in the video, for a $1900 repair .

An air impact wrench will be a big help.
Depending on how badly rusted the bolts are, you might just want to cut through them with a demolition saw (or hacksaw), and put in new bolts.

I’d confirm the diagnosis of the failed converter before I did anything. Eight years seems like an early failure of a cat, but there may be an underlying issue with the engine that caused the early failure. Simply replacing the converter without addressing that issue may ruin the new converter in short order. Looking at the quote may clarify all the work involved.

My Honda dealer is trusted to oil changes, and that’s about it. That’s based on their recommendation to change the timing belt on my 2008 CR-V at 60K miles (it has a timing chain), and their estimate of $360 to change three belts on my 2001 Accord (it has only two belts,and they are among the easiest belts to change I’ve ever encountered). That said, your dealer is not my dealer, but a second opinion may be helpful.

Thanks again for all the tips.

Besides killing polar bears and penguins, is there any danger in waiting until smog test time to fix it?

How do I do that? I admit I haven’t seen that video link yet, but I plan to tomorrow. So if it say how, then nm.

Other than taking it to another mechanic, I’m not sure. And I may be wrong about this, but I think catalytic converter issues tend to show as driveability problems, such as slow acceleration. Your wife presumable only wanted an oil change, she didn’t have any complaints about the car when she took it in for that service, right? Odd how they would be able to diagnose a catalytic converter problem while performing an oil change. Maybe I’m just jaded based on my experience with Honda dealer service.

is your check engine light on? if not, then I really wonder how the shop could have concluded it needed replacing during the course of a simple oil change.

if the catalyst is not working correctly, your check engine light should be on and there should be one or more “catalyst efficiency below threshold” codes stored in the PCM.

that’s because they’re garbage. catalysts are expensive because they contain precious metals like platinum, palladium, and rhodium. cheap ones like that use the bare minimum to be able to still call themselves catalysts, and don’t often work effectively enough to prevent the check engine light from turning on.

This. I wouldn’t cheap out on a cat. I’ve known a few people who ended up replacing there cat twice because the first one wouldn’t work well enough for the cars specs.

I’ve also heard about a few car fires due to bad catalytic converters,(old ones not cheap replacements), so there can be issues beyond performance.

I’d buy a Honda cat so you don’t have to screw around if the engine light comes on after. If you have a code problem with a non-oem part Honda will just tell you you need to buy oem.

According to my estimator, 1900 is about right for replacing one cat (there are two) and the oxygen sensors. It’s way high for doing just the cat.

The question of how it was determined a cat is needed is a very good one. Nowadays most cat replacements are for failure to clean the exhaust properly, and are discovered by investigating a check engine light and finding relevant codes. Alternatively, exhaust restriction (which is somewhat rare) is discovered by investigating noticeably reduced performance. If there were no symptoms obvious to someone driving the car, the diagnosis is extremely suspect.

Field experience has shown that for most cars the aftermarket cats won’t perform properly for very long. Getting one may look like a savings of hundreds of dollars, but in reality it’s almost always a waste of whatever is spent on it.

Typically the fasteners are partly rusted away to where standard wrenches won’t grip them. I find I routinely need to use a torch on them. Cutting with a saw can work – not too bad with a power tool, very tedious with a hand tool.

I’d get a second opinion from a trustworthy shop as to whether a new cat is needed. If it is, I’d take a good look from under the car of everything involved in doing the job before deciding to do it myself.

To clarify: I use a torch to heat the nuts/bolts red hot so that they will unscrew as well as come out of their holes. Often I have to use pliers or special sockets (made expressly for rusted-to-undersize bolt heads) to grip them for unscrewing, as the hex ain’t what it used to be. If the bolts are cut with a saw, sometimes the remaining shanks are rusted into their holes and are very difficult to get out.

A catalytic converter is a "major emission-related component"and thus has an 8-year / 80,000-mile warranty, even on a used car:

Federal Emissions Warranties Are Often Forgotten or Overlooked When Your Car Needs Emissions Repairs

Frequent Questions for EPA’s Office of Transportation and Air Quality

From the second link: *"The Clean Air Act requires manufacturers of light-duty vehicles to provide two federal emission control warranties: (A) “Performance Warranty” and (B) “Design and Defect Warranty.” These warranties are provided by the vehicle manufacturer and apply to used vehicles as well. The warranty period begins from the date of sale to the original owner.

The Design and Defect warranty covers repair of emission control or emission related parts which fail to function or function improperly because of a defect in materials or workmanship for 2 years or 24,000 miles (whichever first occurs), and the specified major emissions control components mentioned above for 8 years or 80,000 miles (whichever first occurs). The manufacturer can deny this warranty coverage if evidence shows that the emission component failure was caused by improper use or maintenance and not caused by a defect."*

For those of us without a shop, lift, and cutting torch, would nut extracting sockets (maybe that’s what you meant by special sockets) work ok? I have a couple sets of these and IME they basically either rip the nut to pieces or allow enough torque to snap the bolt shaft. They’ll get the nut & bolt apart but does that do too much damage to exhaust system components?

Generally, no damage.
The bolts are put through holes in heavy flanges - the flanges are usually undamaged even after serious beating on the bolts.