Cracked Ex. Manifolds

[The Preacher]

So, both exhaust manifolds have a verticle crack in them. Has anyone had success with that goo they sell at the parts store for just such a problem?

I figure it's worth trying before I buy replacements.

I'm not talking about the JB Weld. They have a product just for cracked manifolds.

Thanks for the input.

[andy d]

most goo is some flavor of sodium silicate (furnace cement) it may work on a temporary basis but cures too brittle to handle the expansion and contraction that the cast iron manifold goes through. good luck

[Marvin Gates]

Hey John, I just went through changing the right hand exhaust manifold on my J10, its easier to just go ahead and change it rather than messing around cause you will have to eventually. Make sure you spray the manifold bolts (really soak them) with PB blaster or something like it liquid wrench, Blaster is the best I've found. Spray the bolts where the pipe hooks on also and they will come right off. The easiest way to do the right side is to take the heater box out, there are only 4 bolts holding it in, two inside and two outside, and you will thank yourself for getting it out of the way.
Good luck, its not a bad job just take your time and don't rush it. MG :cool: :D :D :D

[Shake N Bake]

No point fixing em... Just replace them. A used set will probably cost you what the repair stuff does...

I'd have to disagree with marvin, I did it last weekend, and I didn't bother pulling the heater box, access is relatively tight, but easy enough, deep socket was all that was needed to get at em...

Actually getting the manifolds in/out of place was the biggest headache. But just remove one bolt holding the inner fender to the firewall (look you'll see it, not at the edge, in a bit) then pry the inner fender a bit away from the frame, and its a breeze to get the manifolds through the gap.

Andy

[RichCal]

Sealing a manifold crack with anything will last maybe a week, for reasons Andy D mentioned. Been there/done that.
Gotta die grinder? Cut out about a 2" wide by 6" long strip from the inner passenger side wheel well and you'll be able to easily access through the wheel well the bolts rendered inaccessible by the heater box.
If the exhaust manifold bolts are real rusty, one technique to prevent breaking 'em off in the head when removing, is to rap the bolt heads hard with a hammer a coupla times. This will shock the rust-weld loose.
Even if everything goes well its a nasty job.
Good luck.

[The Preacher]

Thanks guys, since I posted I made made a trip to the store and the guy who was helping me re pack my front bearings bought all my parts for me! (he likes his pastor) Well he bought the patch stuff too which was about $10. Since I already have it I may as well try it.

He bought my parts for the next project which is the tranny job. Leaks fluid everywhere. Bought both seals, another one for the shifter hole, filter & gasket. That'll be a big job we'll start in a couple weeks. Which brings me to another topic about transfer cases. I'll make another post about that. Appreciate all the input!

[Marvin Gates]

Hey John, don't let anyone put any kind of oil in the QT except QT oil, it is special and it will ruin it if you use anything else. It is spendy but you only have to change it (depending on how much you drive it) like 50,000 miles. I think I paid $11 a quart, Jeep or Mopar dealers. There are other places but I can't think of them right now. I have sometimers. MG :D :D

[Baldy]

Just as a side note... my exhaust manifold broke into two pieces a couple weeks ago. The interesting thing is that it was the passenger side one, just like everyone else's. Has anyone ever had a problem with a drivers side manifold? Even the ones at the boneyards have the same trend going on....drivers side ok, pass side cracked more often than not. What gives?

[Dome]

If patching them up doesn't work, I have a couple for sale in Colorado smile.gif

[steven79]

The passinger side is the side the heat riser unit it on so it will get hotter than the other one and with cast iron the faster you heat it the more chance of cracking. :(

[beast87]

Just replaced my drivers side manifold last weekend on my 87 GW. Cost me $15 at the junkyard and it came with the air tubes. My advice:Change em both out. If you can find them at your local jy. It's a hassle, but it's better than smelling exhaust gas.
Dave
87Beastieboy