A person I know also has a 99 Silverado pickup with 5.3 L Vortec engine. He asked me to check his codes with my scan tool so I did. His vehicle came up with the P0420 code so I told him what it meant, to the best of my knowledge and what I've read on this forum.

He then asked me what would happen if he did nothing to it seeing as older vehicles never had codes or Cats etc. I said I didn't really know except that it might ruin his engine if not fixed properly.

Was I right? And how soon should he get it fixed? He said he didn't have the money to get it fixed right now but might be able to scrape it up in about 2 or 3 months.

 

It probably won't hurt the engine to drive it that way for a while.

It will not run as efficiently as it could and may lead to other codes popping up the longer the problem is ignored.

Cats do wear out,replace them and be done with it.

 

Tell him to dump a gallon of lacquer thinner in the fuel tank and take it for a long drive on the Interstate to clean that cat up.

Allan

 

I would not recommend doing this

 

Okay, whatever.

Then, spend a half a day crawling around underneath of the thing pulling it off and cleaning it.

Hell of a lot eaiser to just 'burn' it clean. Diesels do it all the time automatically.

Allan

 

I respect your opinion yet I would not recommend adding Lacquer thinner to any vehicle as a fuel system cleaner.....or "Cat" cleaner for that matter.

Lacquer thinner is Toluene...which lowers octane dramatically.
This could result in detonation,extreme cases melted pistons,along with damage to fuel injector "0" rings,fuel filter,02 sensors and fuel pumps.

Sure there is hype around the internet showing how good it can work.

But if your vehicle is a complete piece of crap or on it's last leg that would not warrant to fix correctly by spending money......

Maybe give it a shot and put the vehicle out of it's misery early

By the way Diesels self clean the particulate matter filters by adding extra FUEL to burn them away...all controlled by the ECM.
Just so people don't think it is the same thing!

 

I have heard of additives that are sold to add to the fuel to basically do the cleaning so that a state inspection can be completed and pass, HOWEVER, it is only temporary and will not offer any type of long term fix and will only work a time or two... Replacing the catalytic converter(s) as 67Motorcat stated, is the only real and reliable solution...