Re: Coolant Leak in Vee

[Glenn Merrell <gmerrel@domain.elided>]

Hello Peter and John,
    John is right, the leak is coming from the intake gaskets.  Since
you are going to have to remove the intake manifold to fix the leak, it
is time to do it right.  The mating surfaces of the intake manifold and
cylinder head must be parallel and smooth, no gouges or deep machining
marks, free of all crud and old gasket..  If not, they will leak again
for sure.
    When you remove the intake, clean the surface then run a precision
metal straight edge across the mating surfaces.  If not true, remove
lumps, bumps,  scratches with as wide a file as you can get you hands
on, or a large flat hardwood block and 600 grit sand paper.
    Once you get everything clean and smooth, it is time to check the
amount of distortion in the manifold, or whether the cylinder heads were
set parallel to each other.  Place some gaskets on one side of the
intake manifold, bolt it up snugly, but do not compress the gasket.  Go
to the other side of the intake.  There may be a gap between the head
and intake mating surfaces, but no more than say 0.010 inch, AND it
should be uniform at both places front and back.  If it is as stated,
loosen the other side, slide in the gaskets and bolt things up, only a
smear of grease for a sealer on the intake gaskets because these gaskets
MUST allow motion.  IF IT IS NOT as stated, that is, there is a large
gap front to back, things are NOT parallel...i.e. larger gap front or
back mating surfaces, then the heads have not been installed properly or
the intake manifold surfaces are not true.
    Final bolting of the heads should not be done until the intake has
been bolted up which keeps things on the square.  Often, the heads will
be torqued without the intake manifold in place, and they will not be
parallel if doing this, causing a mismatch of mating surfaces with the
intake.  time and expansion will loosen things up, and the leak starts.

Read ROM section 12.41.05, noting that the LH cylinder head is placed,
then the intake, then fit the RH head, bolt up the intake, THEN torque
the RH head.

Personal assembly preference is to place the timing cover gaskets with
spray on sealant to hold then in place, loosely fit the timing cover,
place head gaskets no sealant, loosely place the heads, place the intake
gaskets greased with water pump grease, loosely fit the intake, snug the
intake bolts, then feeler gauge the four corners of each cylinder heads
and timing cover looking for gaps, torque the heads in sequence, torque
the intake bolts, (remove the timing cover if necessary), then refit fit
the timing cover with bolts, fit the remaining sump bolts.  This seems
to keep things on the square better than the ROM sequence.  BUT, that is
my preference.

Regards,
Glenn  Merrell

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