OnOiShNo0dl3Z

iTrader: (2)

I'm trying to prepare to gut my cats and I'm trying to get all the gaskets I need.

After a few quick searches and calls to dealers, I keep ending up with two part numbers.

My question is to those of you that have replaced Precats or have gutted them or possibly those with headers:

How many gaskets were there and where were they?

Any part numbers?

Where did you get yours and for how much?


For reference the part numbers I've gotten were:
20691P
20692M

HotshotVQ35

iTrader: (5)

my headers came with gaskets, but if you are gonna gut them, just get oem. there would be 3 in total, one at the end of each manifold, and one where the y pipe meets the cat

OnOiShNo0dl3Z

iTrader: (2)

Thanks for the quick reply.

Would there be none between the y-pipe and each precat?

Also, I am trying to get OEM and trying to order them online but I'm having trouble finding them.

HotshotVQ35

iTrader: (5)

those are the 2 i am talking about (assuming you gut the precats on the car), at end of each precat you will need a new gasket..think of it this way, look at what a y pipe looks like, it bolts to 3 locations, on at the cat and the other 2 at the END of each precat, if you remove the precats completely, you probably need 2 more at the top of each precat. 2 people have gutted them on here, maybe they can chime in..

nelledge

iTrader: (6)

I've gutted mine. No need for new gaskets. Reuse. No exhaust leaks here. Months and miles later.

OnOiShNo0dl3Z

iTrader: (2)

@HotshotVQ35 - Yea that's what I meant. I know I'm probably gonna take off the y pipe so i could figure i'll need 3 gaskets there, and for some reason, I assumed that it's necessary to take off the precats from the exhaust manifold as well, which is why I think in total there are 5 gaskets.

@nelledge - Can you tell me how many miles were on those cats when you did this? Would it matter that I live in the rust belt if I consider reusing gaskets?

I don't mind spending 20 bucks for gaskets for security, but I'm just having a bit of trouble finding them. Someone else I asked also reused gaskets and had about 60k on their car at the time.

I'm gonna PM scottwax. I know he's changed his precats before.

dnice02

iTrader: (1)

I didn't get new gaskets. I just used the old ones and hi temp silicon

OnOiShNo0dl3Z

iTrader: (2)

That doesn't sound like a bad idea. Since so many people reused gaskets, it's starting to seem like its not a bad idea. Can you comment on the mileage of the car when you did this?

Rochester

iTrader: (3)

Pretty sure you read this already in that other thread... but my rear-most pre-cat was gutted while still on the car, and apparently was a major PITA; whereas the front pre-cat had to be removed, but gutted almost instantly. As I said in my PM, my mechanic bought OEM gaskets for the job. IDK how much they cost, nor which ones he purchased. But really, they're just exhaust gaskets. How much could they cost anyway?

OP, this is a whole lot of fuss about gaskets. I recommend you find a local in-stock source for the gaskets in case you determine you can't re-use the originals, so that you can pick them up if needed.

2000_MAXIMA_KING

iTrader: (30)

I just reused my gaskets when I got my y-pipe installed because I had purchased the wrong ones (apparently 00 and 01 have different diameter gaskets ) and I've had zero problems.

OnOiShNo0dl3Z

iTrader: (2)

That's the thing Rochester, I did contact my local dealership and they were of no help. I don't mind buying the gaskets but if they can't help, I'm gonna need to find another way.

Other than dealerships, most places don't just stock random OEM maxima gaskets. I don't want to end up having my cats pulled and then have to redo the whole thing

nelledge

iTrader: (6)

I had 120k on the original gaskets. You're adamant about replacing them? Do what Rochester said. Contact a Nissan dealer and order them. Your Nissan dealer can't get it right? Move on to another Nissan dealer.

I'm pretty sure these are the replacement gaskets: 20691-30P00, 20691-51E01, 206918J100. Two ring gaskets to the y-pipe and one for the top of the rear pre-cat. The front pre-cat seals itself. No gasket needed. What part numbers did your dealer give you that are in question?

BTW: The ypipe gaskets can be changed in about 5-10 minutes once you've recently loosened the bolts. No big deal.

OnOiShNo0dl3Z

iTrader: (2)

I've contacted about 4 dealerships, local and not local. I got different part numbers from those that weren't local and the local one was useless.

Now that everyone's saying that reusing is fine, I'm most likely going to stick that route if I can't get the gaskets.

nismopc

iTrader: (3)

I gutted front pre-cat two weeks ago. My '02 has 164K+ miles on it and I reused original gaskets. No leaks. I see no reason why you would need to replace them because of the design.

Stormzusmc

iTrader: (17)

not reading thread after people said reuse gaskets...

if youre cheap enough to not spend a couple bucks on gaskets then im sorry...

when you break the seal on a gasket or crush ring its not going to get compressed the same way so the metal fatigue on it is going to be at a different point....sounds gay and what not, but its best to spend a couple bucks to replace them before you drive down the road smelling your exhaust all day....

2000_MAXIMA_KING

iTrader: (30)

Like storm says replace them man! go to courtesyparts.com and order some, the only reason I reused the crush gaskets cuz i had the wrong ones and found out in the middle of install and there was no going back

036mtmax

iTrader: (11)

Rochester

iTrader: (3)

Winner.

OP, if you're in the middle of this job, and for whatever reason you can't re-use your originals, you're going to be stuck for a while. Go ahead and pick your favorite metaphor for the situation... there are plenty to choose from.

There's a lot more torque on bolts connecting exhaust parts than there are, say, on the VIAS plate. Plus, these are hardened steel contacts, not soft aluminum.

Buy some new gaskets and buy yourself some peace of mind in a job done right.

nelledge

iTrader: (6)

Protest, eh?

Couple bucks, huh? Evidently, you haven't purchased these gaskets before. How about you send me those three new gaskets, and I'll paypal you 2 bucks when I receive them. I'll even throw in the 50 cents for postage.

You were making a valid point until you had to keep talking and this gibberish came out. Stick to explanations you're certain of and your point will be well taken.

OP - It's always advantageous to use new parts. However, there are times when the parts supplied are not accurate or the work was not premeditated. Your original post suggests that you were anxious that the former may happen and you could not put your car back together. This is not one of those times. I dropped my precats on a whim while doing some other work. I had no new gaskets on standby. The relative ease and convenience of changing the gaskets allowed me to tackle the job without the new gaskets. It just so happens that I haven't had any leaks(like several others), and I haven't got around to fixing what isn't broken.

Rochester

iTrader: (3)

Well, this is fun! nelledge has convincing writing skills, I'll give him that.

Reminder: the OP lives in PA, with 4 months of solid, salty winter. I'm guessing phrases like "relative ease" don't apply.

nelledge

iTrader: (6)

I'll take that.


Ahh, but you see. It will be hard to remove the connections whether he has the gaskets or not. However, once removed, disconnecting the pipe again a week later should be accomplished with relative ease should he need to replace the gaskets. I'm guessing they're not putting salt down in August?

Rochester

iTrader: (3)

That's a good point. Now I see what you're getting at, cowboy.

nelledge

iTrader: (6)

Brilliant minds... As it were.

nismopc

iTrader: (3)

Apparently no one mentioned that these so called "gaskets" are not the typical flange gaskets that deteriorate over time.

There is absolutely no reason to spend the extra money (at least on the front pre-cat).

As I stated, I have over 164k miles on my '02 and the precat to manifold and to y-pipe sealed perfectly after I gutted it. No gas fumes, no spitter/spatter, no moisture drops, nothing.

I have not been able to get to the rear yet, so I can not comment on the type of "gasket" used there.

But your choice. You can buy them, then return them if you don't need them.

Gemner

iTrader: (4)

definitely take the cats off the vehicle to do it. will make it easier and eliminate the chance of you busting some cat material up and through an open exhaust valve

OnOiShNo0dl3Z

iTrader: (2)

thanks for that one nismopc.

After looking at the pics and seeing that the gaskets looked like metal rings, and not your typical crush gaskets, I'm starting to think I might just reuse it.

And Gemner, that's pretty much my plan was to take the cats straight off. I figure that way It's much easier to access the catalyst material and I can ensure I get it all out. Since I'm doing it at home without a lift, it'd just make things much easier than leaving it on.

nishfish871

iTrader: (5)

I've got to say the rear precat is a bish to do while on the car. I tried to take it off but it broke my #14 socket. Time for some pb blaster and a hammer. The front precat is very easy to do, it all falls out with a few punches. I used the old gaskets and I have 130k miles.

Did you guys remove all the crap that sticks to the inside wall of the precat? I'm sure I would have to use a degreaser or some strong chemical to get it all out.

jeff5347

I gutted both my precats last year around this time. Like Nelledge and NIsmo stated best to take off the cats. The rear is a PITA but doable. ALoow a couple hours with beer, swearing killing anyone that starts to talk to you during the rear precat gut. I used a butane torch to heat the bolts after i soaked them with wd40 and they came off like a wh@res dress. The gaskets i reused and didnt buy anything to do the job. YOu wont get any leaks, exhaust smell or weird complications. The only exhasut smell will be from the tip of the exhaust as it now will smell like a normal car.

036mtmax

iTrader: (11)

^^^^ This

036mtmax

iTrader: (11)

It is an absolute physical impossibility to gut the rear bank pre cat while on the car so heat the bolts if you can till there cherry red, let them cool a bit and crack them loose.Take your time it sucks to do.

Rochester

iTrader: (3)

What? No, you mean the front. The rear is a straight-up design, whereas the front has a bend in it. My rear pre-cat was gutted while still bolted to the manifold.

Costee

Pardon my ignorance folks, what's it about gutting the cats? Does it entail replacing the components in the cats with new ones?

036mtmax

iTrader: (11)

No,the rear bank pre-cat has to be taken down to gut it.Neither of the manifolds have to come off.Both pre-cats can be dropped without touching the manifolds.The front bank pre-cat is the easy one to gut.Rear bank is against the firewall.Either you got your banks mixed up or for some weird reason our cars are setup different which i doubt.No matter how many of these you have done it's impossible to gut the rear bank while on the car period.

Rochester

iTrader: (3)

I'm starting to think you and I have a different interpretation of which cat is front, and which one is rear.

Would it clarify things if I said front-most, and rear-most?

036mtmax

iTrader: (11)

Front cat is the one right behind the radiator and the rear is the one against the firewall.You are confusing the heck out of me over here...Not like that's hard to do most of the time but im pretty sure im right.

Xpcgamer

iTrader: (5)

So why would it be that impossible to gut the rear cat while on the car? Because of the material? Everybody says its a metal mesh of some kind.

HotshotVQ35

iTrader: (5)

how does one confuse front and rear precats

NmexMAX

iTrader: (22)

It has a little Pt in it, hard stuff.

036mtmax

iTrader: (11)

Yep,it's a mesh that looks kind of similar to the back of your typical household a/c unit or like radiator fins.There so compacted in there it's crazy/I guess that's where the majority of the sound and power increase comes from when you get it out.

036mtmax

iTrader: (11)