Quote Originally Posted by Pepino View Post
Now, since I went into deep water and I am 100% sure the exhaust was underwater is there any chance that water could have ran all the way to the cat converter?
What other things could have blocked my cat?
Mechanic says after letting the VX running and not moving, catalityc converter starts glowing red of how hot it gets. I still have to see it in person.
Not likely that water backed up into your cat unless you turned off the engine whilst it was under water. The exhaust pressure would have kept it from flowing that far up the system. If you turned your engine off, then absolutely it could have.

Yes, the cat can get cherry red ... but it usually doesn't. Even if it's not cherry red, it's still HOT!!!!. That's one of the issues with 'swimming' any cat equipped vehicle. Hitting the cold water with a hot cat can cause some really wonky things to happen. Metal just doesn't like to be cooled that rapidly.

IIRC, the way a cat works is that it contains rare metals (platinum I think) that react with the exhaust gasses. The chemical reaction causes the heat that is used to burn up any unspent fuel and other nasty stuff that isn't supposed to be in our atmosphere. Hence the name catalytic converter ... or catalyst. Believe it or not, the cat is actually sacraficial in that regard. It will eventually use itself up. They are designed however to not get used up for a long, long time (hopefully the life of the vehicle).