Coolant leak in take manifold chevy ?

IMO fix it properly before it blows to the inside and takes out the whole engine. Fixing it properly to me means taking the intake manifold off and installing new gaskets.

Before you do this you might try a re-torque on the intake bolts and see if it seals up.

To my understanding this is a common problem. Had the same problem several years ago. Agree with other poster have it fixed correctly and not have to worry if its fixed or not.

Had a 98 2500 w/454 and had to do intake gaskets at about 50,0000 miles. Common issue. Randu

Will try the retorqe intake bolts, if no help, new gaskets.
Thanks

Turtle n Peeps wrote:
IMO fix it properly before it blows to the inside and takes out the whole engine. Fixing it properly to me means taking the intake manifold off and installing new gaskets.

This.

GM went cheap on intake gaskets from this time frame. That is all. Not coolant related or anything else. A good Fel-Pro gasket will solve your leak forever.

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

I had an intake leak on my 1996 C1500 with a 5.7. Wish I got it earlier..

Turtle n Peeps wrote:
IMO fix it properly before it blows to the inside and takes out the whole engine. Fixing it properly to me means taking the intake manifold off and installing new gaskets.

Before you do this you might try a re-torque on the intake bolts and see if it seals up.

X 2 and my choice would be Fel Pro gaskets.

I would highly recommend getting top quality aftermarket gaskets and not replacing the ones on the engine with the ones from GM. Labor cost will be the same and GM head gaskets are notorious for failing.

If coolant is getting into the intake manifold the first symptom is a loss of power, particularly when the engine is cold as the coolant is inhibiting combustion.

Small amounts of water could also be getting into the oil chambers and this will cause a lot of sludge issues.

I agree with everyone else. Get it repaired right. It is not that expensive.

Paul