PMTXJ

Hey all, I'm new to the forums here, I've poked around looking for good advice for a while but this is my first time posting.
I've had a cracked exhaust manifold for a good while and I'm finally getting around to fixing it. My budget is very limited and I'm looking for some help on what the best way to go about fixing it is. I want to do a good job so that I don't end up having to replace it again soon but without breaking the bank. I've heard of a lot of people welding them with mixed results, I am looking at that as a cheaper option but I want the fix to last. I also have read that a lot of people have had trouble fitting the APN headers on the 99 engines. I am looking at this ceramic coated Speed Daddy manifold
http://speed-daddy.com/exhaust-syste...l6-yk-tj-xj-zj
but it looks a lot like the APN one and I need it to fit out of the box as i don't have access to a grinder to modify it. Any recommendations on durable manifolds that anyone has had good experience with around the $100 price range would be greatly appreciated as well as any input about welding my stock one. I am also thinking about new engine mounts because I have read old engine mounts are a big contributor to cracking manifolds. What are thoughts about replacing with similar to stock vs. upgrading? Any input will be much appreciated!

Deoje

I have a 99 Sport. For what it's worth I changed my exhaust manifold a few years ago due to a crack in the factory unit. I went with the APN unit. I did not have to grind anything. I remember it being sort of a pain to get installed but I did not have to grind.

Who knows if yours would be the same or not but that one in the link looks a lot like the one I put in.

Hopefully someone with more experience will come along and provide some more definitive info.

Good luck.

andrewmp6

Check your motor mounts they are the leading cause of cracked exhaust manifolds.And honestly i would go oem or spend the money to get a pricey better made header.Some of those cheapo headers can crack just like the manifold did.

4x4jeepmanthing

hey nice blackcheroky!

I to have a 99 and i had my exhaust manifold replaced with something looking like this: https://www.summitracing.com/parts/r...FYKDaQodtnICfw

manifold:
i didnt choose the manifold at the time i wasnt mechanically involved with my jeep and just paid to have it fixed. so far so good 5yrs running. much of the aftermarket world is you get what you pay for. Dont go and break the bank though get something ok/good. shop prices for high/low and choose. I dont know anything about the headers you posted so no input there, though welding never seems to be a good fix because new cracks emerge. itll get you by though.

Motor mounts:
I went brown dog motor mounts (quite reliable),rubber not poly bushings. The vibes from a poly bushing are harsher than rubber, though I do still feel Much vibe compared to stock mounts. If you plan on holding on to your ride for longevity get a quality mount. there are many available with good quality. chain store brands work but the rubber is junk.

In my experience if you are of the opinion: i want to fix it once and likely not bother again, search some options and buy quality product. Its such a pain to spend the same on a few cheap fixes than to spend the same on one fix.

PMTXJ

Deoje do you know if yours is a late or early 99? i've read a lot of contradicting things about the APN units fitting into 99's and i'm wondering if that has something to do with it.

PMTXJ

4x4jeepmanthing, I have seen the brown dog mounts and they look nice but are expensive but if they will be likely to keep my manifold in tact longer probably worth the investment. If they dont reduce engine vibration though are they going to be much help over just replacing with OEM.

BTW, my jeep doesn't see a lot of gnarly trails i mostly just use it as a daily driver that I also take to the mountains for snow sports but I want to be able to trust it for towing fairly light loads and snowy, icy, and bumpy roads in the mountains.

teamarctic

Installed the apn header on my 99 classic a few months ago. It was a hassle to say the least. Had to beat some the pipe to clear the intake along with grinding the manifold so the washers would sit straight and clamp down correctly. If i were to do it again, i would go dorman and not have to worry about all that work and have a better warranty.

4x4jeepmanthing

i cant say the BDMMs will be better for preventing a manifold from cracking, thats really more an issue of the manifolds build quality which some aftermarket companies address with the flexing tube on the top of the manifolds. a cracked stock manifold is pretty much guaranteed at some point. you could check the condition of the downstream exhaust mounts if your worried about exhaust pipe vibe/movement.

OEM mounts will work fine for your purpose but the cheaper rubber does degrade sooner. stronger aftermarket mounts with poly or better rubber bushings last longer but do have a bit more vibe. either way its not an item you need worry about replacing often.

PMTXJ

Thanks a lot for the input guys, this has been very helpful. It sounds like for my purposes I should avoid APN or anything that looks like it for ease of installation and I'll probably be fine with OEM mounts or something on the cheaper side. I really appreciate the input.

Deoje

Mine was built 5-99.

Let me rephrase my original post. I didn't have to do any grinding, but that is not to say that it was an easy install. One of the other options might be much easier to install.

extrashaky

Keep in mind that Brown Dog gives a 10% forum discount if you ask for it. That doesn't make them cheap, but it does help a little. The OEM mounts are fine. Brown Dog and Ironman are bulletproof.

Another option for your exhaust is to find a used exhaust manifold in a junk yard. It should cost you $20 to $30 at one of the u-pull yards. 2000 and 2001 had a different exhaust setup, but '99 and earlier should fit yours. Keep in mind the same exhaust manifold was used on other Jeeps with the 4.0L as well. Just make sure you're getting the one-piece manifold and not the later two-piece design.

You'll want to inspect carefully for cracks, of course, but chances are good you'll get one with many more miles left in it.

PMTXJ

I have considered getting a stock one from another jeep but I figured it would probably just break again pretty quickly, am I incorrect in thinking that a dorman or comparable replacement would last me longer than a fully intact stock one?

4x4jeepmanthing

new rebuilt vs old stock having x amount of life/stress already applied. dorman or such will suit you fine unless you plan on some kind of performance build down the line.

s346k

i had mine welded 40k miles ago and it's still fine. also replaced the drivers side motor mount. no issues thus far.

extrashaky

Mebbe. Mebbe not.

Some people get 400K or more out of their stock manifolds, so you might pay $25 for one that will outlast your rig. Or you might get one that cracks the week after you install it. I would be looking at the condition of the motor mounts on the donor rig to see if it has been subjected to more stress than average.

I haven't heard a lot about the Dormans cracking, so it's probably a fine $100 choice. It all comes down to whether you're willing to gamble $25 and your time to save $75.