98 lesabre, o0420 code..some cleaning ideas!

[MarkM66]

Originally Posted By: LeakySeals
I would go with the $5 fix. Use a Dorman HELP spark plug nonfouler modded for the rear O2 sensor. It backs the rear O2 out of the exhaust flow a bit, which the ECU thinks is awesome catalyst efficiency. In a day or 2 poof, out goes the light for good. But remember, that oil burning will eventually plug the cat, and the car will choke and stall. And cause other various issues due to heavy oil consumption. And if you're fogging your cats with pale oil (AKA Seafoaming) don't. Plugs the cat even worse.


Yep. O2 Spacer to the rescue....! O2 sensors were money out the window.

 

[Ethan1]

Originally Posted By: harrybosch
Did some reading on the internet, found out that I could reset it by temporarily disconnecting the battery. As time went by I started to get the CEL more and more, was having to disconnect the battery twice a week.


So I don't really know where to begin with this. Why were you so intent on preventing the light from coming on?

 

[ziggy]

I bought a gallon of liquor thinner last night,walmart,half a tank of gas. Gonna run it over a week or sooner. I did look under the car yesterday, trying for a bit, too remove downstream sensor. Using a crowfoot. It's on their pretty good. Looking at it,I don't think the sensor was ever replaced,in 19 years. The bottom,thread,is rusted,and looks pretty seated in thier. Sprayed a lot of liquid wrench in it, started car, for 15 minutes,turned off. Tried again. Won't budge. Have a breaker bar,but gotta get car up more,for room for breaker bar too move.
Gonna try mmo. Last time I did an 02 sensor, 6 years ago,95 neon, the upstream,it stripped the manifold housing n broke a tiny piece off it.I used so much pressure on the ratchet, a big 3/8 drive...it stripped it. So I know to be careful doing this.but the memo at least,for it too budge!

 

[ziggy]

If it's a new car time..it's not that expensive,technicaly. Rickauto,I can get one for $124. The problem is,current exhaust setup,on the buick, it's almost all welded. Only bolted parts,are the muffler tailpipe too muffler,and from car too manifold.4 bolts on a square end. The rest,resonator muffler.other end of cat,are welded together.
heck of a time,getting the 02 sensor housing off. The wire,had a long metal box covering it,held in place with metal plugs.used a screwdriver,Peter it off. Gonna see if autozone has plastic plugs. Too fit..I have a lot of auto bolts,see if I can use those, just big enough so the threads catch the body holes,too hold the wiring box.

 

[ziggy]

I'm planning on doing the sensors tomorrow.it's gonna be a while,all day most likely,too do both.getting them off,and re threading the holes.bought a 02 hole re threader.
At least yesterday wasn't a waist. Installed new a.c. Delco air filter,and a.c. Delco wires! Filter in thier,was a mann. Still looked goid. Wires were perizoil I believe it said,and had automate plugs.they were burnt,black ended,used. Notid in the old wires,some green and white dep osits. Used my ob ii scanner,again,too erase the code, but it popped back on again,after 25 or so minutes of city driving.
Sometimes, changing the sensors works.it's a gamble. As far as it looks too me, 19 years old, 111,800 miles, they've never been changed. I belive,your supposed too change them,like every 60,000 miles? That could cause this code too,old o2 sensors.or do sc o try kilme r said.

 

[ziggy]

Thought about using a 22 mmm box and wrench, or a big pipe wrench.don't wanna get into using a torch and all that.

 

[ziggy]

As a refresher...the 92 sensor is on the passenger side,downstream. It's lefty loosey ,righty tighty ,right? And for the re threader,I want too turn the threaded right, not left?same direction the sensor threads in?

 

[harrybosch]

I don't like to drive a car with the CEL on, maybe it wouldn't bother other people

 

[Lubener]

After reading your series of posts, are you sure you haven't hit the egg nog already?

 

[ziggy]

Lol I guess not.the coolant has still gone down some,not allowed t. I'm thinking,the block is cracked somewhere,or headgasket. Got a bottle of k&w coolant seal,pour and grange bottle. The level of coolant,from too of radiator,goes down too just covering inside it, the inside top. Dunno if it goes down more, as I've been topping it up too radiator top, every 3 days. It's about 2_3 ozs. Dexron.

 

[Lubener]

You should seek professional assistance and see where you stand with it. Now your guessing and chasing your tail and don't make sense most of the time.. I wonder if you are really serious.You have lived under that hood for some time now and time may be coming where you need to cut your losses and dump your Lesabre.

 

[ziggy]

Well! I put a gallon of Wal-Mart's laque r thinner in,exactly half a tank. The cell light went off! But...it's at about quarter of a tank. Dunno how many miles i did,but the light came back on. It was off,after driving x amount of miles.
Should I try a second treatment? I read a guy did this method, laque r thinner,and after 3 half tank tries,his p04020th went out.

 

[mk378]

I'm almost willing to bet that the converter is hollowed out. You found a hollowed out thermostat, so it is clear that the previous owner liked to tinker.

 

[ziggy]

Yes merkva,I was thinking this week's ago.howevrr,I believe the intake manifold i replaced,is leaking,or,cracked block. The coolant level,went down some more,looked last night. It's getting too cold out,to redo this,so gonna try hard leak intake and radiator pour sealant ,too get me through too spring. Like april. I noted,when the company started too find its way into the cat,the cat makes this brief rattling noise, the cell goes on,3 days after topping off, the radiator level down. Cell is off, me coolant loss, cat seems too work fine.

 

[ziggy]

I believe,it's the lower gaskeys,I need too redo. The sidebar plastic ones. I had noted,after doing this,the intake bolts, 2 had coolant around them. Didn't torque them right . I loosened them, not all the way,3_4 turns left ,the in sequence,testified them too like 197 inch lbs.so it's not 189 inch lbs.not by much,you know?

 

[71Chevyguy]

That job just has to be done 100% correctly, by the book, if you want good results. Honestly, if you are pouring sealant into the cooling system, you can just plan to get rid of the car, because that stuff just ruins everything. Each and every bolt has to be spotless, including the threads it is going into, the gasket surfaces have to be spotless and cleaned with lacquer thinner to make sure they are as clean as they possibly could be. I used blue loctite on every intake bolt on mine, both upper and lower, and made sure everything was torqued properly to spec in the sequence and stages by the book. You can't loosen bolts after the gaskets have been torqued down either, that is just the way it goes. Did you install the little aluminum chimney looking restrictor into the lower manifold for the EGR? There should have been two to choose from in the kit. I have put 10,000 miles on mine since, and everything in perfect, but it was done right, no exceptions or excuses. No offense man, but it just seems like this project may have been a little too complicated for you and it may have been best to let a shop do it instead of tackling it on your own. When it comes to engine work there is only one way to do it, the right way.

 

[LeakySeals]

Originally Posted By: ziggy
Well! I put a gallon of Wal-Mart's laque r thinner in,exactly half a tank. The cell light went off! But...it's at about quarter of a tank. Dunno how many miles i did,but the light came back on. It was off,after driving x amount of miles.
Should I try a second treatment? I read a guy did this method, laque r thinner,and after 3 half tank tries,his p04020th went out.

Any update? Is the P0420 still gone?