Why change my cracked OEM header?

I have a 97 auto 4.0 XJ 4x4 RE3.5 with 32's. Had a long hard weekend wheeling, now I have a cracked header just before/at the collecter, and at one of the muffler joints.

All exhaust is factory stock, and has 107,xxx miles. I know everyone changes there header, but it aint cheap! What are the down falls of just leaving it?

At $119 is the APN one any good? Seems like a bargain.

thanks for your input!

your engine compartment could overheat at stops if you dont, a shop with a mig could fix it for much less than that. if you take it out and put it back in, depends on how bad it is.

I think it can cause your rings to burn up eventually.

Just get the $150 china made Banks knock off.

Check your engine mounts - failed/failing engine mounts seem to accompany header collector cracks in most cases, I've noted...

5-90

when I look at the engine mounts, I assume it will be easy to see, but is there anything specific that I should look for?

I know this sounds dumb, but just wanna make sure before I replace header.

leaking exahaust gases in front of the cab can enter the cab and make you go night-night while driving. It will also make an aweful noise, cause your O2 sensor not to get a correct reading since gases are leaving the exaust before the sensor. if your state has emmisions or safety inspections your vehicle will be failed for a cracked header/manifold. I've also heard that it will burn the rings. it will also cause more pollution since the cat converter won't have a chance to filter the exhaust. just change it. its not that big of a deal.

it will also give you really crappy gas milage too

Just do it. Like everybody mentioned, a cracked header will cause your engine to run too rich and raise underhood temps, giving you poor fuel economy, rough running and increased component wear. My gas mileage went up after i changed mine and the Jeep idles better. I did however pass the visual and tailpipe smog inspection with a cracked header. But, here in So Cal most smog "techs" have no clue what they're looking for anyway, and I've only come across a few that understand even basic English. While you have the intake and exhaust manifolds off, the motor mount is right there and easily accessible for replacement.

I reccomend that you get a new style header with the flexible sections, rather than to try and weld the old style header. If you weld it, the crack will eventually reappear.

Red97XJ-I replaced my motor mounts just for fun to make sure they wouldn't fail anytime soon. I didn't know that one of them had a HUGE split in it. With the weight of the motor on it you couldn't see it was broken.

You may be able to jack up the motor and check the rubber mounts to see if the rubber is separated. Otherwise just plan on replacing them when you replace the header. You'll take off your intake & exhaust manifolds, then R&R the motor mounts, then install your new header and intake manifold.

I used the APN one and it's been great so far. If you have a decent assortment of wobbles/extensions it isn't too bad to torque all the bolts. I've heard people whine about how they couldn't get them but I put a torque wrench on every single bolt/nut. I'm not saying it was EASY, but you can do it.

later,
Nick

screw torque, tighten the damn things until theyre tight and recheck in a few days, mine is cracked and my exhaust is falling off too, too bad i dont have the cash to fix it...

DO NOT have it welded up. Thats what the previous owner did to mine and well it recracked a week into my ownership of the Heep. I beleive mine is cast which you cant weld properly and with it heating and contracting repeatedly its bound to crack again. Purchase whatever you can afford and install it/have it installed. Then when you can afford a better exhuast you are all set for extra ponies.

Bottom line, you get what you pay for in a header, spend less, ull be cracking it again...

I will try and take a look at my mounts. Are they expensive? Hard to replace?

I expect to be replacing my motor mounts with the Bomb Proof mounts from Mountain Off Road. Well, when I swap in the APN header this winter.

This is on my 95 Grand... Will likely add a XJ or two this winter as well...

change it because its a fun project!

the apn header is a decent deal, not bad to replace the oem with.

motor mounts surprisingly weren't too bad. They looked easy enough to get to. I went for it in my apt's parking lot. LOL I tried swapping out the left side first, but was not able to reinstall the big bolt (you'll see once you look at it-big bolt runs front to back horizontally) because I could not get the motor to line up. I was nervous to do it for fear of not EVER getting the motor to line back up, but I pulled the big bolt out of the right side of the motor too. That meant the motor was just sorta floating sitting on top of the jack.

After pulling out the right side big bolt I was able to get the left side to line up and drove it home. Then I spent an hour or two trying to line up the right side. I just couldn't seem to get it so I called it a night. I left it with the bolt halfway in overnight. By letting it sit overnight the weight of the motor squished down the right motor mount and I was able to get the bolt all the way through after maybe 10 mins of trying.

I used the stock motor mounts because I didn't want extra vibes of a polyurethane mount, and I didn't feel like ordering it and waiting. Stock sets seem to last 100k+ miles, and that seems like a long damn time right now. NAPA had them in stock and they cost maybe $20-$40 dollars for the set.

All in all not too bad of an install. Easier than I thought it would be, and HEY, I did it in the middle of a friggin parking lot!

later,
Nick

does autozone carry the mounts? how many are there and whatever else you need?

miketyson said:

does autozone carry the mounts? how many are there and whatever else you need?

Click to expand...

yes they do, if you wheel hard at all the stock ones wont last well and move too much, you will tear them up quickly

I have never noticed any additional vibes from a correctly built set of poly mounts



When installing new mounts always only take one side out at a time.

also loosen the trans crossmember to allow for side to side movement, place the crossmember on a rolling jack and about 1/2" below the studs. you can use a jack or ratcheting strap around the trans/tc to pull the engine mount assembly into alignment. then reverse the process to realign the crossmember, using this method it usually only take me about an hour to do both sides and reattach the crossmember