What's with the right exhaust manifold on FSJs?

[88Woody]

I don't know if anyone else has noticed it, but why does it seem that the right exhaust manifold has problems on these FSJs. When I bought my GW, the exhaust manifold had a leak. I found a newly wrecked GW in a wrecking yard soon after, and it had the right manifold taken (the left one was still there). Is there a problem with the design of these manifolds or is the hook up to the block? I am going to put on edlebrock headers soon, but am worried that whatever is causing this will render my investment useless after some wear. Any thoughts?

Bryant

[JEEPGUZZZI]

The right side is where the heat riser is. I bet that has something to do with it.

[shadowfax101]

Mine leaks as well, just from that side. I wonder if it is a conspiracy smile.gif smile.gif smile.gif

[Nagy]

I too have a small leak on the right side of my 89. Can't seem to find it.

[JEEPGUZZZI]

Could be that you need a donut over there, or the heat riser has cracked. They are notorious for that.

[xj2fsj]

mine worked fine till i replaced the gaskets

[Bombadier]

yeah, it seems to be a design defect or sumthin. 'cept my driver's side manifold is MUCH worse than the pass. side one. actually, i don't think the right side is really that bad.....i'd know fer sure if it didn't sound like a crazed chipmunk playing the spoons in my engine compartment. :eek:

[Marvin Gates]

The right exhaust manifold on my J10 had a spot in the center of it on the outside that looked like charred wood and had some hair line cracks that were leaking. Got another one, when I took the old one off the place that looked burnt just fell out (about a 2 inch circle). Kinda strange for cast iron to sorta melt.It was right in the middle where the two cylinders exhaust comes out.
After talking to some people I guess its a more common thing than I thought it would be. MG

[ May 09, 2002: Message edited by: Marvin Gates ]</p>

[Gargel-orum]

its seems like its just the manifolds in general..

My drivers side manifold has a crack too, and come to think of it- before i bought my wag, i test drove MANY cheros and wags both w/ 360's and I6's, and they all had that card in spokes sound coming from one of the manifolds (bad seal or crack)...

It definantly seems to be a design flaw, but i wounder.. Is it the factory manifolds that are shotty (meaning new headers/manifolds will do the trick) or is there something with the engine set up and parts placment that causes the warping, deteriorating seals and cracks?

i think we ought to take a poll- factory manifolds vs. replacement headers/manifolds

[ May 09, 2002: Message edited by: High Gargel-orum ]</p>

[AusTex 72Wag]

Let's talk. The other day, driving home doing about 70 or 75mph, I heard a slight hiss... then my exhaust sound went large. I've looked for a leak in the tail pipe/muffler but could find nothing. I DID NOTICE, however, that the "heat-riser box" that comes off the passenger exhaust manifold has an opening at one corner; I don't ever remember seeing it there before (and I do my own tune-ups and even have replaced the alternator, etc. so should have noticed it).

Might this be my problema?

I've spent the better part of a day loosening rusted exhaust manifold bolts in the event I need to replace the gaskets. I've also started the process of spraying Liquid Wrench on the bolts where the tailpipe connects to the exhaust manifold, in case I need to replace the doughuts there (but if they're too tough to remove, I'll pony up for my dual exhaust transformation to save myself the labor!)

[effle18]

I just took the manifold off of my 258 and where the manifold and exhaust pipe meet at the donught was all rusted and cracked and as soon as I touched it, it crumbled. This was surprising to me as well because this is thick, thick metal.

[joe]

<blockquote>quote:</font><hr>Originally posted by High Gargel-orum:
It definantly seems to be a design flaw, but i wounder.. Is it the factory manifolds that are shotty (meaning new headers/manifolds will do the trick) or is there something with the engine set up and parts placment that causes the warping, deteriorating seals and cracks?<hr></blockquote>

It's not a design flaw, it's called old age. That cast iron has been heated/cooled expanded/shruck how many times in the last 15-20+ years?
I've had the same probs with exh manifolds on SBC, Toyo LC's, Fords you name.
"Stuff is old and worn out...it happens"
If you think you've had a lot of grief from the iron manifolds...try running tube headers for twenty years and compare the grief/maint and number of times they leaked in the same period(assuming the don't rust and/or burn out way before the 20 years are up).
If your manifolds are solid remove them and take them to a machine shop and have the mating surface machined to get them flat again. Most old manifolds can be salvaged this way...some though will be just too far gone and need replacing.
It's just one of those maintenance things... smile.gif

[Marvin Gates]

Hey Joe, you mean cast iron is like my old body (it falls apart),you make a very good point. MG :D :D :D

[joe]

Yeah Marvin...pretty similar smile.gif
Exh maifolds are even more neglected than front driveshaft CV joints. They'll get a small relatively quite leak then slowly get worse. In the mean time a couple years go by and then the rig is sold. The new owner is like most folks...hates to mess with them cause of the fear of breaking off a bolt and it's still a bearable leak right?. Another year goes by till it's really time to fix them. During all this time hot spots develope and warp the iron where the hot gases have been leaking out rather than going through the manifold. Prolly cystalizes or whatever at the hot spot(it's been 35 years since I've had any metallurgy classes) and that weakens things and can cause the iron to disintigrate and at best just warp. It's an even worse prob on long inline six manifolds where there's more length for them to move. They'll often crack where the shorter V8's won't if you don't let it go too long. In most cases they can be machined flat again and it's pretty cheap to have done...way cheaper than new cast iron manifolds or good tube headers which are a pile of grief all their own :(

[Marvin Gates]

By the way I did break a bolt off in the head (exhaust manifold bolt) flush with the head. I had to do some dismantling of things to get a straight shot at drilling it out. Everything worked out fine and its nice and quiet again. In the past my worst nightmare was breaking off a bolt in the head. It wasn't near as bad as I thought, important thing is take your time and don't get in a rush.MG :D :D :D

[Michael]

Mine was cracked right down the middle on my '87.... made is sound like it was open exhuast by the time I replaced it. Once replace i have had no leaks!!!!

[RustyJeep]

I just pulled off my manifolds 10 minutes ago. It took me 10 minutes to get both off...I was very very suprised at the way the manifold bolts jst zipped right out. Also, the nuts for the exhaust flange on the bottom of the manifolds zipped right off too. The manifolds are perfect, and were quiet...I just wanted to pull the to remove the AIR tubes and to cleam them up, get them surfaced, and to paint them with POR-20 high heat coating. To say the least, I was amazed.

[LHopper]

Some time ago I had to replace the donut on the right side $$$ with the heat riser that is closed when cold,if the heat riser doesn`t open all the heat stays on that side a lot longer. You should check to make sure the reat riser opens all the way. Good luck. smile.gif smile.gif

[Gargel-orum]

-joe

i just say that because- iv owned MANY older cars none newer than 18yrs, and to say the least, i didnt even know what a leaking manifold sounded like untill i started driving FSJ's. And litteraly every FSJ iv ever tested out save one (89') had that problem..but not one of almost 50 (non FSJ's) older cars/trucks that i test drove, owned, friend owned ect.. had that problem save maybe 3 (and the engines of those reflected it). It seemed odd that manifold problems where more present in FSJ's than any other older vehicles.

[joe]

I think it's a maint thing...as in whether or not it's been done. My 73 360 had 175,000 on it when I sold it with stock manifolds and it didn't leak. My 63 inline six 230 OHC doesn't even leak at 85,000(pretty good for a 230) and my 72 360 doesn't leak...&lt;shrug&gt;? Have they been maintained...by me they have and prolly by the PO's too.
My only point was FSJ 360 manifolds aren't any worse than others if they're checked once in awhile. Your experience has been different than mine I guess but that's what I've concluded in almost 40 years messin with cars. Personally "I" think in some cases the later a vehicle the less quality of construction/components appears...at least in US stuff?
The again sometimes we buy cars at the right time of there life...and sometimes we don't smile.gif Anyway just get the manifolds machined and be happy you don't have headers to deal with. ;)

[Gargel-orum]

nope..no headers...but got a nice crack in mine, no reman unfortunatly, just gonna through a used one in there for now, then save some cash and get OEM ones