Coolant leak in take manifold chevy ?
Have a 97 chevy k2500 (454 c in)truck. Get a occasion leak between the intake manifold and head, right in the front. I can see the little amount of seepage ocasionally, seams like if i drive the truc...
Forum Discussion
Very common to GMT400's and I almost lost my 7.4L to those issues...CHANGE the
gasket ASAP and DO NOT use any silicone based sealant/RTV...that will get silicone
into the system and poison the O2's
Deathcool is involved, but not the cause of the leak
GM in it's wisdom decided to change the manifold to head design for the sake of
easier assembly. A robotic head to tighten all of the manifold bolts in one fell
swoop by changing the angle of those bolts from square to the sandwich to angular
to the sandwich so that the robotic torque wrench head could do all the bolts
at once
Why the ridiculously low torque of those manifold bolts...IIRC somewhere around 16 in/lbs
Since not square anymore to the sandwich, the sandwich slides and moves to roll
the 'new' 0-ring gasket. Anyone who has designed in O-Rings knows that to twist
it is a no-no and it will leak over time
The new Fel-Pro gasket and OEM gasket solves that by the addition of a 'tab'
that has a mating bore in the head to keep the sandwich from sliding.
Took this image around 10 years ago when visiting an after market 'big brake'
shop in El Segundo. Saw this on the worktable while they were modifying an
Escalade with a Whipple
Notice that the bolting angle is not square to the mating surface with the head
and that new tab to keep it from sliding to then roll the O-Ring gasket
Here is the original O-Ring gasket from a small block that has a Whipple on it
Here is what meant by DeatCool being involved...backwater area where DeathCool
collects and in this case to rot out the metal of both the head and block
gasket ASAP and DO NOT use any silicone based sealant/RTV...that will get silicone
into the system and poison the O2's
Deathcool is involved, but not the cause of the leak
GM in it's wisdom decided to change the manifold to head design for the sake of
easier assembly. A robotic head to tighten all of the manifold bolts in one fell
swoop by changing the angle of those bolts from square to the sandwich to angular
to the sandwich so that the robotic torque wrench head could do all the bolts
at once
Why the ridiculously low torque of those manifold bolts...IIRC somewhere around 16 in/lbs
Since not square anymore to the sandwich, the sandwich slides and moves to roll
the 'new' 0-ring gasket. Anyone who has designed in O-Rings knows that to twist
it is a no-no and it will leak over time
The new Fel-Pro gasket and OEM gasket solves that by the addition of a 'tab'
that has a mating bore in the head to keep the sandwich from sliding.
Took this image around 10 years ago when visiting an after market 'big brake'
shop in El Segundo. Saw this on the worktable while they were modifying an
Escalade with a Whipple
Notice that the bolting angle is not square to the mating surface with the head
and that new tab to keep it from sliding to then roll the O-Ring gasket
Here is the original O-Ring gasket from a small block that has a Whipple on it
Here is what meant by DeatCool being involved...backwater area where DeathCool
collects and in this case to rot out the metal of both the head and block
