Leaking exhaust manifold plug, FJ60 (1 Viewer)

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Has anyone had to replace the exhaust manifold plug that is located just above the exhaust pipe flange on the backside just in front of the manifold temp sensor? Fixed leaking EGR gasket and found this plug leaking like a sieve. Can't find any reference to it in the manuals or parts diagrams.
 
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Are you referring to the bushings (part #s 70 in the image below) that secure the rod (part# 63) for the heat riser (part# 62) to the exhaust manifold?

exhaust manifold rings springs.jpg
 
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there is an expansion plug back there as well IIRC...the small parts depicted in the drawing are not and never were dealer servicable parts; they are just shown exploded for the techs use. I was told Toyota only ever replaced manifold assemblies, not actually repairing them...any really good old skool machinist should be able to source/fashion/fabricate any and all of those parts. rings and springs and heat riser shield were the only things actually considered replaceble(pn 12, 15, 16) SOR actually had some bushings machined for repair purposes, but they have long since been out of stock...
 
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Yes! Thanks to both of you. Just crawled under my 85 (the one NOT leaking) and confirmed. I had looked at this same diagram, but I was so used to looking from underneath that I had myself turned around, and since I have been lucky enough NOT to have had to deal with carb removal or manifold issues (until now...), didn't make the connection to the back pivot on the riser. And none of the diagrams really show the actual plug at the rear. So, now the question is, what to do about it! Assuming the riser is working, and I have no reason to think otherwise, can I simply push some muffler weld or somesuch to stop the leak, or is this leak a harbinger of bigger issues?
 
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I was told Toyota only ever replaced manifold assemblies, not actually repairing them...any really good old skool machinist should be able to source/fashion/fabricate any and all of those parts.

I think LAMBCRUSHER nailed it. Fixing the leak involves either getting a new manifold assembly (if you can find one and are willing to shell out the $$$), or if you have the manifolds off and disassembled then a exemplary machinist should be able to fit new bushings...

...or you could just keep on chugging along with the exhaust leak...

Either way you decide involves trade-offs (and risk, if you try to 'rebuild' the current manifolds). I would say that addressing vac leaks is a higher priority (and worth the time/money/risk) than addressing exhaust leaks...and within the hierarchy of exhaust leaks, addressing gasket exhaust leaks are lower risk/cost than addressing an exhaust leak through one of these bushings.

Those bushings allow the rod (to which the heat riser is attached) to rotate. When the engine is cold, the heat riser (inside the manifold) is positioned in such a manner as to direct hot exhaust gas to hit the bottom of the intake manifold (to warm it up quicker).
Then, when a certain temperature is reached, the coil looking thing (part# 58) expands (or contracts, not exactly sure which)...moving the position of the heat riser so that the hot exhaust gases are now diverted directly down the down pipe.
If you weld those bushings, then the position of the heat riser will remain fixed.
If it is fixed so that the exhaust heat is directed to hit the bottom of the intake manifold, the floor of the aluminum intake manifold will eventually crack, causing an intake leak (your problems are multiplying).
If it is fixed so that the exhaust heat is permanently directed down the down pipe, it will take the engine longer to heat up to operating temperature.
In this case (and if you don't have to pass emissions), moving to aftermarket headers in place of the exhaust manifold might be another option...
 
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manifold could be old, warpped and needing some rnr, but I can't see why some exhaust goop would hurt but it does get pretty hot right there, not sure if the goop is meant for manifolds for that reason alone. if you decide to get it done up by a pro(recommended), provide them with all the rings and springs and heat riser shield and gaskets(dealer or specter) and have them split it, replace the bushings and plug for the heat riser, gently hone or bush the outer horn bores if need be, replace the rings and springs, put new gaskets and shield in and marry them back together, and replace the outer horns and mill the sealing surface flat as a single reassembled piece. without going all the way, it'll continue to bite your arse going forward. use some goop till you can do it right?
 
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Thought of another option is you are considering going with headers.

You could still stay with your current exhaust manifold, just remove the heat riser system (if you live in a county that allows desmog, otherwise I doubt you would be able to pass visual on emissions if you remove the heat riser) and install a block off plate. Off the top of my head, I can't remember who makes it, I'm pretty sure there is a commercially available plate that can be installed to protect the intake manifold. A MUD search would reveal the manufacturer.

Then you could plug and weld those holes in the exhaust manifold where the bushings used to be.

EDIT: just a note that if you pull the manifolds, get the FelPro manifold gasket from your local aftermarket auto parts store, in lieu of Toyota...same gasket but cheaper and comes with the two gaskets (but not the OEM heat riser shield) that go between the two manifolds.
Also, as LAMBCRUSHER suggests, get the faces of the manifolds planed together (search MUD) as well as the seats for the washers on the other side.
If you are going to disassemble the manifolds (as you would need to to attend to the heat riser business) you have to decide whether or not to get the manifolds planed before or after you disassemble them.

If you do it after, you might want to reinstall them, tighten everything down (but not torqued all the way to spec), then remove and plane.

When reinstalling after having taken the manifolds apart and put on new gaskets between them, I fasten the 5 bolts that hold the manifolds together VERY LOOSELY, then position the manifold assembly into position on the engine on top of the down pipe and with the new gasket between the head and manifolds.
Then I LOOSELY fasten in all the manifold-head bolts and the three nuts that go to the down pipe.
Then I bring in the head-manifold bolts/nuts to finger snug (following torque pattern), then same with the down pipe and then 5 bolts holding the manifolds together.
Then tighten down the head-manifold bolts/nuts, followed by down pipe to torque...and lastly tighten down the 5 bolts holding the manifolds together.
 
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Going to try to get a better look at it with an inspection mirror today. I think the bushings are intact, just the plug is cracked. May be able to seal the leak with something called Thermosteel (also marketed as QuikSteel Xtreme). Seems the better option that taking apart the manifolds that seem to be fine other than this plug issue. Can of worms... Leak is significant enough that it makes it uncomfortable to drive. On the vacuum point, just replaced all the vacuum hoses, replaced the EGR VSV, and put in an in cab Vac gauge. Pulling good vacuum now. Just need to cut down on my carbon monoxide intake! More later.
 
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there is an expansion plug back there as well IIRC...

Probably true, on later models. The earlier ones (like on my '81 manifold assembly - that picture above refers to this early '81 manifold assembly) are simpler...if you find the parts diagrams for later models (including yours) you will probably find a few more parts in the heat riser assembly...presumably Toyota was trying to improve (mitigate exhaust leaks) the performance of the heat riser assembly...
 
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Going to try to get a better look at it with an inspection mirror today. ... Leak is significant enough that it makes it uncomfortable to drive....

How are you identifying exhaust leaks? Smoke test?

What performance issues are you attributing to the exhaust leak? Stumbling during acceleration?
 
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Ah, excellent! Had no idea the manifold shown was only early. Good reminder that all FJ60s are not created equal. I know my 84 and my 86 have very different steering. Tracked down newer diagram (actually on this forum) and it clearly shows the expansion plug and part number. Nice. Now I just have to track it down. I double checked with mirror and my other Cruiser for comparison, and it really is just the plug that popped out. Riser assembly seems fine.

To Slow Left: Using the shopvac in the tailpipe method. Brilliant! Allowed me to track down leaks in both Cruisers that had eluded me, without sending up a cloud of white smoke. I think the performance issue was mainly from the missing EGR gasket. Now just trying not to asphyxiate myself. That little plug holds back a lot of exhaust!
 
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Tracked down newer diagram (actually on this forum) and it clearly shows the expansion plug and part number. Nice. Now I just have to track it down.

If you post up the part number and tag @beno in the post, he might be able to tell you if that part is available or not. He works for Toyota in Atlanta...
 
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Discontinued.

There you have it... @RedBeast , you might still try searching the interwebs...maybe one of the online aftermarket Toyota parts hoarders still has one or two on the shelf...? Or maybe post the part number and a picture of the part up in the 'Classifieds- Wanted' section here on MUD for a used one?
 
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Thanks! That word you never want to hear - discontinued. I am kicking myself for not sprucing up my 60's earlier, as each year "discontinued" gets more prevalent.

However, I seem to have found the plug, or its replacement, at Toyotapartszone. The part number in the diagram is 17141H, which translates into
96411-12000 PLUG,TIGHT,EXH.MNFLD
Replaced by: 96411-42000

Will report back on how tough/easy it is to tap this into place. I think I have sufficient room for a hammer and something to set the plug with, but whether I can get two arms up in there is a question!
 
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Thanks! That word you never want to hear - discontinued. I am kicking myself for not sprucing up my 60's earlier, as each year "discontinued" gets more prevalent.

However, I seem to have found the plug, or its replacement, at Toyotapartszone. The part number in the diagram is 17141H, which translates into
96411-12000 PLUG,TIGHT,EXH.MNFLD
Replaced by: 96411-42000

Will report back on how tough/easy it is to tap this into place. I think I have sufficient room for a hammer and something to set the plug with, but whether I can get two arms up in there is a question!
 

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My bad. Looked at the wrong part.

96411-42000 is indeed available and applicable.

Sorry for the alarm. My Sanka hadn't kicked in yet.
 
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Must be plug 17141H here on this diagram?

It does look like it would just get pressed in, somehow...

...notice how it's missing on the earlier model? Bummer for me...with the '81...

The other side of that heat riser rod looks alot busier, too. @Output Shaft , this diagram also shows only one set of rings on each exhaust horn for the earlier models. When I reinstalled my horns last week, I just kept the old ones on there and filled the other groove for each horn with a new set...that way the old springs and rings can train the new ones how to do their job well...

manifolds 2f USA.JPG
 
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Red Beast, I am dealing with an exhaust leak from this same plug on the heat riser. I see that you ordered the part back in the fall. Did you have any luck getting it pressed in w/out removing the manifold, etc?
Thanks for an update!
 

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