Intake manifold leak, GM V6

General Motors V6 with intake manifold removed shows dramatic evidence of gasket leaks, a very common problem in these engines. Using plastic, aluminum and steel in major engine components leads to gasket problems, since the materials respond differently to heat and vibration. The dark liquid on top of the motor should not be there. It is mostly transmission fluid that entered the intake through a leaky transmission modulator, then leaked into this area by way of a cracked plastic upper intake manifold.