Replacing catalytic converter

bigBP · June 28, 2004

Here's the story.

One of the donut gaskets that goes inbetween the y-pipe and the exhaust mainfold blew on me one day, resulting in a very noisy truck ('95 chevy C1500 4.3L). Took it into Tuffy to get it checked out and the guy told me that my cat was clogged and the resultant backpressure buildup caused the gasket to fail. He recomended replacing the cat w/ front y-pipes along with the new gaskets and studs. Here was the estimate:

O-2 sensor $160

cat w/ front y-pipe $423.90

truck stud kit (2) $63.90

Labor $75

The grand total after taxes and such was $766.44 . Is it just me or is this estimate a little high, especially the 0-2 sensor?

At any rate, I'm now considering on replacing the parts myself, with the holiday weekend coming up. Replacement looks pretty straightforward, but I have heard that with rusty bolts it can be a real pain in the a**. Thanks

95_togo · June 28, 2004

uh YEAH - seems a bit high to me - but what do you expect when taking it to a shop for repair.

i think the O2 sensors are about $70 but could be mistaken - and aren't there 2? that would give you your $160 estimate roughly

as far as replacing the front Y pipe and Cat - i have had much custom work done on mine, as i keep wearing holes in my front "cross" pipe with my 5-7 drop - but they keep cuting and welding a new pipe on for me for around $30 - as far as the CAT, i had mine replaced for under $200

too bad you aren't in AZ, i could tell ya a shop to go to!

snoman · June 28, 2004

Here's the story.

One of the donut gaskets that goes inbetween the y-pipe and the exhaust mainfold blew on me one day, resulting in a very noisy truck ('95 chevy C1500 4.3L). Took it into Tuffy to get it checked out and the guy told me that my cat was clogged and the resultant backpressure buildup caused the gasket to fail. He recomended replacing the cat w/ front y-pipes along with the new gaskets and studs. Here was the estimate:

O-2 sensor $160

cat w/ front y-pipe $423.90

truck stud kit (2) $63.90

Labor $75

The grand total after taxes and such was $766.44 . Is it just me or is this estimate a little high, especially the 0-2 sensor?

At any rate, I'm now considering on replacing the parts myself, with the holiday weekend coming up. Replacement looks pretty straightforward, but I have heard that with rusty bolts it can be a real pain in the a**. Thanks

This has a funny smell to it. Never heard of a dounut gasket blowing froma plugged up cat but I suppose it is possible. Personally I think he is looking for some extra income. I would just replace gasket and roll and if vehical runs fine, that cat is not plugged. (and they do not plug that much anyway)

95_togo · June 28, 2004

This has a funny smell to it. Never heard of a dounut gasket blowing froma plugged up cat but I suppose it is possible. Personally I think he is looking for some extra income. I would just replace gasket and roll and if vehical runs fine, that cat is not plugged. (and they do not plug that much anyway)

definitely looking for extra income in my opinion too - however, the cat is old, and probably has a lot of miles on it - aren't they usually only good for about 100K? i replaced mine with 130ish on it, and it improved my emissions drastically!

AZ-Z71 · June 28, 2004

Don't know much about 95's but do you have any SES lights on that would throw a code for CAT or O2 Sensor?

snoman · June 28, 2004

This has a funny smell to it. Never heard of a dounut gasket blowing froma plugged up cat but I suppose it is possible. Personally I think he is looking for some extra income. I would just replace gasket and roll and if vehical runs fine, that cat is not plugged. (and they do not plug that much anyway)

definitely looking for extra income in my opinion too - however, the cat is old, and probably has a lot of miles on it - aren't they usually only good for about 100K? i replaced mine with 130ish on it, and it improved my emissions drastically!

My 89 burb has 170k on its cat and it still flows fine and I have a Toyota camary with 215k on its cat, I got both of them new and they test emisions here and they still both work.

AZ-Z71 · June 28, 2004

My 89 burb has 170k on its cat and it still flows fine and I have a Toyota camary with 215k on its cat, I got both of them new and they test emisions here and they still both work.

Also depends on what state. Some states are really tough like California. Az is also pretty tough these days as well. Had an Infiniti with 120 K on the cat, no SES lights on and I could not get it to pass. Got a new cat, it passed and two years later it failed???

Fixed that problem - got rid of the car along with the wife.

bigBP · June 28, 2004

I don't have any warning lights going off, and the engine seems to be running ok. Is there any easy way to see if the converter is really clogged besides banging on it? Also, the estimate for the O-2 sensor is for one. Heck, the highest list price I've found on the internet is $90 for a Bosch. Would really like to know where Tuffy gets they're numbers from.

Really, the only thing I'm concerned about is the noise, going down the expressway I have to crank up the radio to hear it. I wouldn't mind it so much if it was a V8 .

snoman · June 28, 2004

My 89 burb has 170k on its cat and it still flows fine and I have a Toyota camary with 215k on its cat, I got both of them new and they test emisions here and they still both work.

Also depends on what state. Some states are really tough like California. Az is also pretty tough these days as well. Had an Infiniti with 120 K on the cat, no SES lights on and I could not get it to pass. Got a new cat, it passed and two years later it failed???

Fixed that problem - got rid of the car along with the wife.

Here they give you print outs of limits and what is detected (CO, HC and NOX) and both are way below limits (about 10 to 15% of limit) and they have not changed even 10% of that in last 7 or 8 years as I keep them so I get a warning if a problem is coming.

AZ-Z71 · June 28, 2004

I would probably just change the donut gasket and be done with it. I think they are ceramic and will probably break and crack over time causing them to leak. I think the shop that did my exhaust system used the old gasket as well. Now after a few months I can see some black carbon at the joint and when cold the condensation drips rom the joint. I don't seem to hear anything from it but maybe that is my cold tick I have been experiencing. (Not sure since the volume/pitch does not change when applying gas)

Buy the donut gasket and two studs and nuts. That way if you break the studs, you will have the replacements there. Cheap insurance.

bigBP · June 29, 2004

After some tinkering around and debating, think I'll just take AZ-Z71's advice and replace the busted donut this weekend. Thanks for all the advise

snoman · June 29, 2004

After some tinkering around and debating, think I'll just take AZ-Z71's advice and replace the busted donut this weekend. Thanks for all the advise

I alway farm that out becuase thoses studs can be stuck and rusted and a pain to work with. I muffler shop will have the tools and a torch to heat them and get them out and install new studs too. You might buy the correct donut gasket yourself though and take it with you.

Rookie · June 29, 2004

Id replace the manifolds w/ headers, new cats Fron Catco and have a local shop plum it together. O yea dump the o2 sensors and put a O2 simulator in there Casper electronics makes them.

snoman · June 29, 2004

Id replace the manifolds w/ headers, new cats Fron Catco and have a local shop plum it together. O yea dump the o2 sensors and put a O2 simulator in there Casper electronics makes them.

Yeah disable your emmisons so we can all breath a little harder. Also, headers will raise underhood temps too