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304 manifold leak? 304

speed__demond

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hey all my car (vs 304, duel fuel) has a flat spot when accelerating harsh and runs rough when accelerating normaly, the idle also changes between 600-800 every 10 or so seconds.
I tried the wd40 trick around the manifold/injectors and the idle did change, either dropping 100 or raising 100 nothing above 900rpm tho.

im pretty certain its a manifold leak but did wanted someones advice that's tried this trick before... its hovering idle as it is so I wanted to be certain before I take the manifold off...
should the revs raise more? like a few hundred or?

ps ive checked the vac hoses, and there also happens to all of a sudden be a small oil leak around that area near where I think the manifolds leaking, can oil leak from the manifold???
 

drewVHSS

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re tighten all your bolts and see if it improves
if it does, take one bolt out at a time and clean it up and dip in a tin of the holden head bolt sealant and put each one back in.
I've had leaks due to bolts lossing tension over time and also had individual bolts leak (usually at the water ports) coolant up past the head of the bolt

either that or bite the bullet and pull the manifold off and renew gaskets
 

Ian Johnston

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Inlet manifold gaskets leaking is a common problem with 304 engines if they have done a few ks.
Get it fixed properly.
 

mr j-man

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id just pull the manifold and give it a fresh pair pair of gaskets and a reseal with some permatex blue sealant....good opportunity to check some internal components also
 

ari666

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mr j-man

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cant hurt, can it?
definitely not!
For the sake of a 30 buck pair of gaskets how could you not.

I pull of mine every 6 months just to check cam lobes and lifters because I get bored lol..well at least once a year
 

speed__demond

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definitely not!
For the sake of a 30 buck pair of gaskets how could you not.

I pull of mine every 6 months just to check cam lobes and lifters because I get bored lol..well at least once a year
haha ur keen, ive been doing too much lately so im at a (small) point of I cant be farked if I don't need too.
Im doing it this weekend anyway, hopefully its worth it
 

ari666

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hopefully its worth it
if you just smash the intake off and on again, then it wont be.

if you clean the absolute bugger out of the whole intake, inc TB IAC etc etc, suss out **** in your valley, check this and that, make a day of it. then yeah 100% worth it, even if it doesnt fix your vac leak.
 

mr j-man

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Id even port match my manifold whilst I was at it too....definitely worth it then and would pickup some HP gains too....free horsepower who doesnt want it lol
 
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