Think cats are clogged need opinions.

[Bigshawn]

@PNW VietVet i never heard of that i will have to check it out. Yeah I'm thinking 20 years of salted bumpy asss roads and heat cycles. They will probably be darn near impossible getting them out without breaking or busting something. Well I'm going to look up this Aero kroil and put a list of stuff to buy so I don't forget something. I know the stuff is going to be gulded to each other from experience. My drivers side brake rotor took about 4 hours to get off cause it was rusted an just wouldn't move. Went thru 2 cans of penetrating oil, me and my brother just kept taking turns hitting it with a mini sledge and it was not bugging. So my pap lives like a half mile away i got him to come down and help cause I was so frustrated. We had to put a bolt with 2 nuts thru the caliper hole and keep pushing against it until it finally popped off. Smh it was unbelievable the rust and junk came off of it. Anyway sorry for going of subject but thanks everyone for the help

 

[OR VietVet]

Aero Kroil is kind of expensive but you don't have to use as much and it works. Don't have to saturate the area. Best to do it, according to your rust story, 3 to 4 times and let sit for at least a couple hours each time. If you can also somehow "shock" it with a hammer on the flat sides where the wrench/socket will sit, that helps. I used to watch a guy use a wrench he did not care about, put the box end on the sensor flat spots and use a ball peen and shock the wrench with the hammer and first hit it as like you are tightening it and then shock it loosening it. I have even seen him hit the outer round part of the wrench also. He would also use an air chisel with a flat nose punch and do small shocks to the sensor.

The key is not too hard that you damage the sensor "bung".

 

[rockola1971]

Aero Kroil is kind of expensive but you don't have to use as much and it works. Don't have to saturate the area. Best to do it, according to your rust story, 3 to 4 times and let sit for at least a couple hours each time. If you can also somehow "shock" it with a hammer on the flat sides where the wrench/socket will sit, that helps. I used to watch a guy use a wrench he did not care about, put the box end on the sensor flat spots and use a ball peen and shock the wrench with the hammer and first hit it as like you are tightening it and then shock it loosening it. I have even seen him hit the outer round part of the wrench also. He would also use an air chisel with a flat nose punch and do small shocks to the sensor.

The key is not too hard that you damage the sensor "bung".

Thats the first thing I do when I come across a stuck bolt, sensor, etc....Tighten it. This usually breaks loose the crap in the threads that is seizing the whole party.

 

[Bigshawn]

Ok thanks @PNW VietVet and yeah that aero kroil is a little bit pricey definitely won't be using 2 cans of it in a couple hours. I don't mind spending money on something that is worth it. One more question might sound dumb tho, is there different cats on like a 01 sierra, tahoe 5.3 than a yukon(i know different for NY and CA) cause I was reading reviews on Amazon and one person would say it would fit and the next person would say it wouldn't.

 

[OR VietVet]

I checked RA and looked up the 01 Sierra's, Tahoe's and Yukon's with the 5.3 engines and they all took the same catalytic convertor part numbers, depending on Federal or Ca. emissions and there were two choices of Ca. emissions. I looked at the Walker applications.

 

[Matthew Jeschke]

I am not a parts dart kind of guy. 240k on my rig o2 sensors work perfectly. I have hp tuners so can watch the waveform created by their readings. That said, I would do the vacuum test...


Also if you know the rears are bad then that is their function, to test proper operation of cats.

You should replace known bad sensors as your computer will give false readings otherwise. Unless your intention is to trick the computer...

 

[easymoney]

My 01 yukon 5.3 has 334,000 miles and P0430 and P0420 codes are both coming up but it doesn't feel like they are clogged. I've ran some techron and cataclean thru it about 10k miles ago but didn't help with codes. I'm afraid of dumping to much money into it with the miles that are on it but it's still running strong. I looked on rockauto and can get new cats plus the 4 o2 sensors for like 300 to 400. What do you guys think? @Tonyrodz always value your opinion

With that many miles your over due. I fought the same thing at 150k. Replaced some sensors but it was the cats so wasted time hoping it wasnt the cats. I drilled a hole in the pipe before the cats and had a very sensitive pressure meter and they were not clogged. I stompped on the gas and couldnt get any back pressure over 0.5 psi. I figured that wasnt clogged.

They generally through a different code if the o2 sensors are bad but theres always a chance its the sensor but its a low chance. The factory cats were all welded but the aftermarket ones i got slipped on with clamps which was pretty easy to install and i figure if it fails again i can unclamp it and reinstall another one. Took about half a day of work but been good for 3yrs so far…i messed with that for about 2 yrs trying to get it to passs for inspection. It lasted a while then code would come up. Over and over again. Sounds like you have some money if you value your time just do it ALL with quality parts no cheap ones. If you want to save money i agree replace the sensors and see if it makes a difference. There is a very good chance this will be a waste of your time.

My opinion its not that expensive to just do it it all and save the frustration. When you get it fixed you wont miss the extra couple hundred bucks.