That tells you nothing if it was clogged up it would not get red hot were did you learn that?


Whack it a few times good and hard if you hear rattling inside then its clogged

 

Use a vacuum gauge. It's easy to test for an exhaust obstruction.

 

I actually learned that from experience. I have had a clogged cat before. The honeycomb inside the cat was scrambled which was blocking the passage way for the HOT air to move through, which therefore made it get super hot and start glowing red because of the heat. Very simple. Vacuum gauges may work. I know its not the cat or muffler though, thanks for the input

 

The vacuum gauge WILL work to tell you about an exhaust restriction.

You're assuming it would be the same problem with the cat as before. It doesn't have to get that hot, to glow.