Skip the auto shop - Our mechanics make house calls

Q: Is my Catalytic Converter bad?

asked by on

Last week the sharp rattling noises began. Mechanic diagnosed bad Cats...

Waiting for weld shop to get new cats in and didn't drive the car. Today I drove to work and there was zero noises...

Taking car to shop tomorrow but need to know if this is normal for the rattling to just stop...

Btw, performance seems normal during all the noise/no noise the past six days...

My car has 49000 miles.
My car has a manual transmission.

Hello - yes, it is possible that catalytic converter is busted. This ceramic honeycomb is fragile, and a good whack on the converter from a good size stone, or a speed bump that was a bit too high, can easily break the honeycomb from impact on the case. The pieces can become hot enough to "glue" themselves back together - temporarily, but since the honeycomb is directional (exhaust gases flow through them -- over a platinum catalyst), the odds of them aligning correctly are similar to winning the lottery. You are doing the right thing by replacing them.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: I have water and fuel in my oil

You most likely have a coolant leak into the engine through an intake or a head gasket leaking. If you have water in the oil it may damage the crankshaft bearings if ran too long with the water in the...

Q: I HAVE 1999 CHEVY TAHOE 2 WHEEL DR.MNI REPLACED THE ROTOR,CALIPER AND PADS ON DRUIVERS SIDE.WHEN I WENT TO TEST DRIVE IT THE CALIP

So that the vehicle will not pull upon braking, pads and rotors must always be replaced in "pairs", that is both sides of the axle should be serviced whenever brake repairs are performed. There are many possibilities for the damage...

Q: Van won't start

Hello There, The neutral safety switch can often times be the culprit of no start issues and would have been a good place to start. I would also recommend checking the starter relay as this can often times produce the...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...