Rotted out EGR diaphram frame

Trukage · May 14, 2025

Hello,

A very ol' 4.3L HEI with Carb.
Been having an intermittent problem, Seemed to think ignition related(might still be)
but, the only thing left to replace would be the pickup coil and vac. adv. diaphram.
So While perusing over things and possible vacuum leaks etc., I noticed that the
EGR valve is (Fried). I am going to remove it and put a plate over where it mounts
on the intake manifold(front: near thermostat). It is justso freakin' old and lets just say rusty.
I wanted to ask, if anyone has seen these bolts snap in the manifold. I will take some
precaution of this, I figure on throwing some heat on them(prior to some PB blstr).

Thoughts?
Thanks, Trukage

SYptoMz: no idle... complete loss of power(not that there ever really was power [4.3L in full size truck,sih!]...... Serious dawg....

Edelbrock · May 14, 2025

If the bolts snap off, you may be able to "glue" the plate on with the high temp gasket sealer.

Trukage · May 14, 2025

Thanks for the idea. Yeah, last thing I want to do at this time is
be removing the intake manifold. Really, would like to drop in
an 8 popper... Just so maybe I could think of passing on the dotted yllw.
Those slow pokes!.
Have you used the high temp gasket maker in similar
desparate situations?
Geeze, what are the chances of both bolts breakin'.
(I promise to be car*full) :banghead:

Edelbrock · May 14, 2025

Trukage said:
Thanks for the idea. Yeah, last thing I want to do at this time is
be removing the intake manifold. Really, would like to drop in
an 8 popper... Just so maybe I could think of passing on the dotted yllw.
Those slow pokes!.
Have you used the high temp gasket maker in similar
desparate situations?
Geeze, what are the chances of both bolts breakin'.
(I promise to be car*full)

Can you post pics?

Ricko1966 · May 14, 2025

If the bolts break,which they probably will if this is an aluminum manifold,NBD drill a pilot hole,drill that hole tap drill size,and tap the holes,very common. You said you are going to use heat,good idea,and penetrant,probably a waste of time on an aluminum manifold beacause galvanic bond is the problem,but it doesn’t hurt to try, one last thing smack the heads of the bolts a couple of times with a drift and a hammer to help break the bond loose. If that doesn't work I have another trick up my sleeve. Post back and tag me if necessary, it's more involved but will still be mechanically fastened and a lot more sure bet than hoping something stays glued under heat and exhaust pressure.

CountKrunk · May 14, 2025

Sounds like you need to LS swap it

Edelbrock · May 14, 2025

CountKrunk said:
Sounds like you need to LS swap it

Na, that wont work. The rusty EGR bolts have a different thread pitch than what would be on an LS. He would never be able to install the rusty EGR bolts on the new motor....

Trukage · May 14, 2025

Well, I guess I got something going for me.. That would
be that the Mani is cast iron. yr.86. I will post a pic when
I get a chance.
Thanks for all the input.

I hope to put a 2500 Burb's V8 in it. So just trying to
keep her happy without getting overly involved in the 4.3L.
She has 200K on her and is rather bubbly in the heater core(head gaskets).

Finkaire · May 14, 2025

California, can’t help you

Trukage · May 15, 2025

Ah, Go west young person.

Will see about a pic. little hectic(heretic) today

Ricko1966 · May 15, 2025

Trukage said:
Well, I guess I got something going for me.. That would
be that the Mani is cast iron. yr.86. I will post a pic when
I get a chance.
Thanks for all the input.

I hope to put a 2500 Burb's V8 in it. So just trying to
keep her happy without getting overly involved in the 4.3L.
She has 200K on her and is rather bubbly in the heater core(head gaskets).

If you have leaky headgaskets,you are wasting your time trying to make it run right,until those are fixed.

Sad Sack · May 29, 2025

Trukage said:
Hello,

A very ol' 4.3L HEI with Carb.
Been having an intermittent problem, Seemed to think ignition related(might still be)
but, the only thing left to replace would be the pickup coil and vac. adv. diaphram.
So While perusing over things and possible vacuum leaks etc., I noticed that the
EGR valve is (Fried). I am going to remove it and put a plate over where it mounts
on the intake manifold(front: near thermostat). It is justso freakin' old and lets just say rusty.
I wanted to ask, if anyone has seen these bolts snap in the manifold. I will take some
precaution of this, I figure on throwing some heat on them(prior to some PB blstr).

Thoughts?
Thanks, Trukage

SYptoMz: no idle... complete loss of power(not that there ever really was power [4.3L in full size truck,sih!]...... Serious dawg....

After the heat and PB Blaster don't immediately go to loosening them, instead just try to cinch them a little tighter then loosen them.

squaredeal91 · May 29, 2025

CountKrunk said:
Sounds like you need to LS swap it

That's @squareroots line lol

TotalyHucked · May 29, 2025

I'd recommend soaking in PB for a couple days before hand, 1-2 applications a day, then heat, more PB and then try to remove. Works 99% of the time for me

Rotted out EGR diaphram frame

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