You can't just drop new bolts in the holes where the broken bolts came out of. The manifold has to be removed and the broken bolt ends removed with an EZ-Out or at a machine shop. While the manifold is off, you can take one of the bolts to an auto parts store for match-up and buy the bolts you need.
If it is leaking from a bad head gasket, it is because of a bad head gasket. If it is leaking from a bad intake manifold gasket, it is because of a bad intake manifold gasket.
Most of the time - yes
Because it 's leaking- OIL, ANTIFREEZE, or vacume leak
Intake manifold is leaking, or worse, cracked cylinder most likely tho, the intake manifold.
Intake manifold at top of engine?
Most likely the intake manifold gasket is leaking.
most time it is caused by intake gasket failure
Intake manifold gaskets are leaking, intake manifold is warped.
leaking gasket try tightening the bolts a little might help
Usually when you leak oil that's an indication that the intake manifold gaskets need to be replaced or your intake manifold is shot.
If really on top then probably the intake manifold gasket ,study it closely .
What's under the intake is not a hose, it's a pipe which a hose attaches to behind the intake manifold near the firewall. If the hose is leaking, it's a relatively easy task to replace it. If the pipe is leaking, you will have to remove the intake manifold which is not an easy task (minimum 6 hours to remove and replace the manifold!)