The GM 5.7 that typically leak antifreeze leak at any of the four corners of
the intake where it meets the head. The problem is not the manifold, but the
gaskets. Eventually the antifreeze will leak into the oil and if ignored the
lower end, main and rod bearings take a beating. The gaskets are plastic,
with a silicone sealing strip and the plastic cracks letting the silicone
"blow out" causing a leak.
If you are unable to do the good yourself, find ask around for a shade tree
mechanic, or a small one man shop to do it for you. Ignored you are asking
for major problems!
My '93 5.0 leaked, my dad's '97 5.0 leaked, my neighbors '97 5.7 leaked, my
'95 5.7 work truck gaskets failed too. All failed the same! I think all
5.0-5.7's will fail sooner or later!
One company I worked for would run GM vans 300,000-400,000 miles. Some of
those vans had been repaired three times!
Greg

"Roy" wrote in message
...
Yes lots of manaifolds have coolant passages in which anti freeze
passes through......


I currently have a 1997 GMC with 350 and its always leaked or should
I say used anti freeze......starting about the time the warranty went
out..Too costly for replacement but the way I understand it I am not a
lone individual with a GM plastic manifold coolant leak either. Mine
best I can tell is not in or around a cylinder, and its going out ther
exhaust which I hear is what most cracked GM manifolds on the 350
does........true or not I don;lt know, but no signs of leaking coolant
externall, none in oil.....

On Sat, 21 Jan 2006 16:20:56 -0500, Bob Engelhardt
wrote:
Jeff Wisnia wrote:

... cracked (or maybe just
warped) plastic intake manifold ...
... wouldn't even crank
because of hydraulic lock from the antifreeze in one or more
cylinders.
...

Antifreeze is circulated in the *manifold*?

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