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My Successful APN header install

On a side note, I got this header in 2008 and i noticed it has a crack in one of the welds. Anyone have to deal with warranties with the company yet? It should be covered, I'm just not sure if I have to remove it and ship it to them before I get a new one.

Oh, and does having a crack in the manifold make the idle rough (other than the horrible air sound at the crack)?
 
What did everyone do with their old exhaust manifold? I cant quite bring myself to throw it in the garbage quite yet.

Hope you figure out the warranty process. Let us know how it turns out.
 
Mhopton you seem to be a natural with the tools. GearWrenches are great so many times it's the only thing that will fit.

I'd recommend not using flex tube it's ugly and unneeded. I put my APN header in about a year ago still no cracks. Even after being rear ended and the whole exhaust system getting tweaked it still holds.

XJFever said:
Oh, and does having a crack in the manifold make the idle rough (other than the horrible air sound at the crack)?
Click to expand...

The 02 sensor will read the oxygen from the crack making the engine run terrible.
 
Very nice job. I too am relatively new to wrenching, and this was also the first 'major' repair that i had attempted on my own. i however used one of the cheapo 70$ headers off of Ebay (which 6 months later is still just fine).

I however didn't have those sweet, sweet, flex head gear wrenches. used about a million different extensions and a lot of odd positioning under the XJ and plenty of swearing to get mine done:) still took me a little over 5 hours.

but the sense of accomplishment is very rewarding.
 
Mesh said:

I'd recommend not using flex tube it's ugly and unneeded. I put my APN header in about a year ago still no cracks. Even after being rear ended and the whole exhaust system getting tweaked it still holds.

The 02 sensor will read the oxygen from the crack making the engine run terrible.
Click to expand...

Hmmm, i think Joe may be correct. I think my APN has a crack but i cannot determine where the crack is. Is there a way to find and ensure there is a crack without having to remove it? I get the aweful exhaust leak coming from the header area and it goes away as the engine warms. I also get lousy idle and exhaust farts from the manifold area after a hot start (o2? from crack or gasket?) and some intermitent hesitation/bucking when hot and highway running. I used the supplied gasket and if i have to remove the manifold a FelPro is definitely being used.
BTW it's a 96 4.0, 99 intake and have had no problems for 2 years.
Thanks for any tips! :cheers:

Great write-up and congrats on doing the work yourself, very relaxing and rewarding! -B
 
Mesh said:
Mhopton you seem to be a natural with the tools. GearWrenches are great so many times it's the only thing that will fit.

I'd recommend not using flex tube it's ugly and unneeded. I put my APN header in about a year ago still no cracks. Even after being rear ended and the whole exhaust system getting tweaked it still holds.


The 02 sensor will read the oxygen from the crack making the engine run terrible.
Click to expand...

Who would ever see or notice a 6" piece of flex pipe near the cat?

Worn motor mounts let the motor rotate to far putting stress on the exhaust which does not move as far. A piece of flex pipe allows for the independent movement of each preventing the cracks. Unless I'm crazy?
 
what are the gains you've noticed? im thinkin my headers garbage dont even want to look at it
 
great work to the op, did mine last year, nice to see a desk jockey accomplish this. Not that I'm a mechanic or anything but I do work with my hands for a living, it's a great sense of accomplishment. Not that I would ever doubt Joe Peters but I never did the flex pipe on mine, good idea but I just did the motor mounts at the same time, M.O.R.E for me. I'm hoping this will eliminate any future cracking problems. Congrats on a job well done. Keep us posted on the rear main.
 
Agreed on the motor mounts when installing aftermarket headers. In talking to several header warranty folks the most common causes of cracked manifolds are:
1. Loose exhaust hangers
2. Manifold bolts torqued incorrectly... especially overtightened
3. Improperly installed gasket
4. Worn motor mounts/cracked or loose engine brackets

Just reporting what they say....
(Of course, we'd prefer you install our mounts, in any case, it's important that they are in good shape)
 
Last edited:
Excuse my ignorance but what are these GearWrenches you're talking about? I did the APN header install (I'm definitely not a wrencher either) and it sounds like they would've helped a lot lol.
 
http://www.gearwrench.com/catalog/wrenches/ratcheting/flex_combination/

these are so beautiful for this install...

just an tidbit of info: i will be on my third APN header, the first one cracked because of bad motor and tranny mounts, which i paid for the replacement for (i didnt even call about warranty since i kinda felt like it was my fault). the one that is currently installed has developed a crack again, even with new mounts, and i called them up and they will replace it. one of the easiest warranty claims i have ever dealt with. for the price of the header, even if you do have to replace it, its still a damn good deal with the warranty.
 
XJFever said:
On a side note, I got this header in 2008 and i noticed it has a crack in one of the welds. Anyone have to deal with warranties with the company yet? It should be covered, I'm just not sure if I have to remove it and ship it to them before I get a new one.

Oh, and does having a crack in the manifold make the idle rough (other than the horrible air sound at the crack)?
Click to expand...


UPDATE WARRANTY INFO:

The manifold I bought is covered under warranty and the company is in the process of shipping me a new one right now. APN was really great about the process too. I could either ship my cracked manifold and wait for the new one, which would leave me without a vehicle, or just order a new one and get re-reimbursed for the $$ when they receive my old one. I went a head and ordered a new one; they're also covering shipping both ways. Great customer service!
 
iwannadie said:
I'm not sure why these are always called gearwrenches(on other forums I go to as well) as that is a brand not a type. Craftsman, husky and many others make the same thing, I've always called them ratcheting wrenches.

Not to nit pick, just thought he asked what they are. For the record I never liked gear wrench the brand either :farmer: .
Click to expand...
Same reason people Xerox things still. Ever hear of a Kodak moment? Once a real market-changing product is released and becomes famous, it kinda turns into a product type, i.e. it becomes a "household name." I really like my GearWrenches for some reason, they're quite well made, one of mine I found in a junkyard and it's clearly been abused but still works great.

XJFever said:
UPDATE WARRANTY INFO:

The manifold I bought is covered under warranty and the company is in the process of shipping me a new one right now. APN was really great about the process too. I could either ship my cracked manifold and wait for the new one, which would leave me without a vehicle, or just order a new one and get re-reimbursed for the $$ when they receive my old one. I went a head and ordered a new one; they're also covering shipping both ways. Great customer service!
Click to expand...
Awesome, always like to hear about companies that actually handle things right.
 
Just in case someone could use this information, make sure you have someone hold the front most part of the intake up as you tighten it down. I made the mistake of not doing that and ended up with a vacuum leak.

BTW, great writeup-the gear wrenches worked like magic.
 
TIP: For future readers
1. Use brake cleaner for cleaning sealing surface.
Throttle Body/ Carb Cleaner will leave a residue behind, brake cleaner will NOT.

2. If your Exhaust manifold cracked (usually due to failure of motor mounts)
replace with Brown Dog, or M.O.R.E. mounts, unless you enjoy replacing headers.

3. Re torque while hot after a few thermal cycles, then yearly there after.


 
I just replaced the header in my 98 and i go all the way back to the installation of the TB. this is where i thought it was going to be easy however i have sensors that do not appear to have a spot to be plugged in. is there are diagram or anything that could help or should i just keep looking?
 
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