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-   -   Can JB Weld Extreme Heat save my exhaust manifold? (

Xist 06-17-2019 12:46 AM

Can JB Weld Extreme Heat save my exhaust manifold?
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Whenever people try a project like this people say "Just get a new one from from a junkyard for $10-25!"

It has an integrated catalytic converter. I do not know how to find a used one aside from purchasing a parts car.

The cheapest combination on Amazon is a Walker 16096 for $222.27, although there are cheaper ones that look right. I do not know what the alleged problem is.

This one for $105 with free shipping says it fits 1996 -1998 for Honda Civic HX.

How are the 1999 and 2000 different?

Rockauto has a Walker 16096 for $232.79 and a Bosal 099884 for $270.89. It calls those "Daily Driver." It has a Pacesetter 755002 for $161.99 and a Bosal 096884 for $294.89 under Premium.

AutoZone has the Walker 16096 for $379.99. O'Reilly's has a MagnaFlow 50602 for $412.99 ($305.41 on Amazon). Napa has one just like the Walker 16096, called the Napa 16096, but for $376.99.

Hey! $3 cheaper than AutoZone!

Do I want to spend $105 on a manifold and catalytic converter that may work or at least $222 for one that should definitely work?

Well, what about welding it?

Napa's JB Weld ExtremeHeat page says:


Cast iron is very difficult to weld, it can be done, but the repairs are usually quite ugly and they donít last very long. A proper cast iron weld require removing the part from service, pre-heating the part to near welding temps, welding the damage, and then slowly bringing the part back to room temperature. Most repair shops donít have the capability of doing this
Makes sense, although both Napa and JB Weld are advertising.

Would you trust someone from Jay Leno's Garage:

He welds the part and I can find other videos of people welding cast iron successfully, but I do not have any equipment. There are only a handful of welding shops in the area.

On Monday I can call around and see what they say, but I would hate to pay for a repair that does not work.

I cannot find too much information aside from 242 reviews on Amazon. It is rated 3.5/5. Going through the one-star reviews, many people describe a watery substance that never hardened. Many others just did not give any details. This review was not encouraging: "I used this on an exhaust manifold. It held for a couple days. After that it kind of just flaked off little by little." [jaamzw] Many people said they prepared it correctly, but I bet there was at least some user error. One guy said to find his YouTube video. I was the fourteenth person to waste time watching his annoying video. He did not show any preparation or even describe it, but it cracked.

I inclined to believe that this guy did something wrong:

15/22 people who mentioned exhaust manifold in their review said that it worked. Did it last? One person wrote that JB Weld held until the car was properly fixed almost a year later, but there is a good chance that at least one person wrote a positive review, only to have it fail later, and they did not update Amazon.

So, this is interesting:

ChrisFix showed how to use this, but cut off the part of the package that said JB Weld, and used marker on the label. It worked for him, but he never reported back.

Here it is before I applied the paste:

It will cure in our garage in Arizona for four days before I work on it again.

mpg_numbers_guy 06-17-2019 01:46 AM

Replace it with the least expensive, known-to-work catalytic converter. Don't go cheap on the fix. Do it once, do it right, and it'll last for a very long time.

Get all new stainless bolts and washers.

Buy some Rustoleum 2000F rated primer and paint and paint everything, especially the catalytic. Bake it as instructed on the back of the spray can.

Install it, do it right, and save yourself some headache down the road. Your car will thank you later.

It can be done for less than $300 in parts all together, including paint, stainless hardware, and any springs and/or gaskets required. Replace it all with new.

Rockauto had the best deal when I replaced mine not that long ago.

Your first attached picture doesn't show up on my end.

Xist 06-17-2019 02:19 AM

Weirdly, the first image showed up on my computer, but no, it was not attached.

I fixed that, thanks.

The instructions say to bake at 600įF for 30 minutes. I doubt Mom's oven goes that high and you would probably never hear from me again if I tried.

Nobody recommend it. It is not funny.

I am sure that I could find one on Craigslist cheaply, but how would I make that work?

mpg_numbers_guy 06-17-2019 02:33 AM

Baking it probably isn't necessary, but I wanted to be thorough, so that's how I did it. Ecky followed a similar process with his and he said that his has held up well, and I'm not sure if he baked his or not.

You could probably find a used one fairly cheap, although finding the specific one may be yours unique to the HX or is it cross compatible with all 6th gen Civics?

People rarely sell used catalytics in working condition; chances are any that are being sold are either rusted out or junk ones that would throw a code if used. Someone might have a parts car with a used one, but in either case I'd go with new, as it's not that much more expensive and is guaranteed to last a while, especially if treated.

Assuming, of course, that you go with an aftermarket assembly, rather than OEM, which I presume would be around $1000 if not more.

Xist 06-17-2019 05:43 AM

Sixth-generation Honda Civic (1996 - 2000) catalytic converter part numbers
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Thanks to I went to several other dealership sites before I found this function.


Weird how the 1998 DX is on both lists.


I read many times that all of those were the same part. I do not know what the difference is. The price varies by about $2.

The Ex and Si have cats located after the downpipe and the Si was not available in 1996 - 1998:



Amazon has mine for $634.60.
Someone is selling a used one on eBay for $300 with a 14-day test period and 90-day warranty.

I have never seen used cats for sale. I always read that they needed to be recertified and people scrapped them instead.

Actually, these guys have one for $243.07 with a six-month warranty. This includes $93.07 for shipping.

$780.64 AcuraHondaPartsHub shipped (Thanks Google Shopping!)
$781.81 Majestic
$979.14 HondaPartsNow (I think this includes the $150 core charge)
$980.58 Bernardi (presumably with $150 core)

$1,030.02 Tempe Honda
$1,144.47 Right Honda
$1,167.36 Bell Honda in Phoenix

I found a handful of other places outside of Arizona, but ones that have historically had good prices do not have the catalog available. Like everywhere else in Arizona, either I get an information request form, or the e-store says "Contact dealer."

Stubby79 06-17-2019 06:39 AM

I'd weld it. Find the best kind of stick/wire for cast iron, use the engine to pre-heat and slow the cooling process. Couldn't get to the back side, of course, but oh well. If it doesn't work, I'd be no worse off and I didn't waste a lot of time, money, or effort on said failure. If it worked, I'd be laughing.

No welder? No money or skills to replace it? yeah, go for the JB weld.

Shaneajanderson 06-17-2019 10:20 AM

I'm just here to say don't buy pacesetter: it's cheap garbage and will rust out in a year or two in the best of conditions. Walker is usually pretty good, as they strive to hold to OEM specs or better in dimensions and materials.

Xist 06-17-2019 11:50 AM

3 Attachment(s)

Originally Posted by Stubby79 (Post 600263)
No welder? No money or skills to replace it? yeah, go for the JB weld.

Hey! Who are you calling poor and unskilled?! I am only poor and unskilled for the foreseeable future!


Originally Posted by Shaneajanderson (Post 600273)
I'm just here to say don't buy pacesetter: it's cheap garbage and will rust out in a year or two in the best of conditions. Walker is usually pretty good, as they strive to hold to OEM specs or better in dimensions and materials.

Don't buy the one with the weird tabs that nobody else has?

It only has four reviews and is at 4/5.

I wish there were other pictures of the Walker, but see? No weird tabs!

Unfortunately, it is only 3.4/5 with 7 reviews. There are fitment issues and it requires 10 x 1.0 nuts (not included), not the OEM 10 x 1.25.

Someone said they should have bought the Dorman 674-439, which Amazon has for $172.95. Amazon says that it does not fit, but five reviewers say it fit their HX just fine.


It is rated 4.1/5 with 144 reviews. I do not know why it is two pieces, although I imagine that it allows them to mix and match as necessary. I sure hope that this lasts the life of the car, but I would rather replace the manifold or the cat, not both. Several people reported this does not come with a gasket that it is supposed to, or the wrong one, although a few said it was hidden in the bottom of the box.

Shaneajanderson 06-17-2019 12:20 PM

I would guess the positive reviews of the Pacesetter were new purchases. I had some pacesetter equipment on an Alero I got in high school: fit up was great, but it rusted out in about two years with minimal salt exposure, and regular washing. And this was a cat-back system, so not even close to the extreme temperatures that manifolds and converters see.

California98Civic 06-17-2019 02:00 PM

This is right up against the engine. Vibrations are going to break a J-B Weld in days. Regular weld the last longer, but it's not going to last. Buy the Doorman and get it overwith. I like how you can separate the Catalyst from the manifold itself, something Honda should have done originally. I also imagine that the Doorman is lightweight compared to the cast iron OEM model. Care to weigh them both and see what the relative weights are?

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