About 4 years ago I had the intake manifold on my 2002 Mercury Mountaineer replaced with a new one with the aluminum front thermostat housing. All was going well for about 1.5 years. Then I started to smell coolant and there was a little steam. Could not tell where it was coming from except back left (facing engine) of engine.
It seems the intake manifold has a rubber cap (1/2" to 5/8" opening) held on by a spring clamp that started to weep through cracks that had formed - so when idling nothing - higher revs I could see coolant. So I replaced the rubber cap - and it failed again in the same way only sooner - 9 months. This cap is directly by the rear most coil pack (passenger side) so when it goes it fills the spark plug hole with coolant.
Question - is this the correct manifold for my car? What is this coolant hole used for? Are they suppose to have this bypass cap? What is this cap called? Does anyone have a Ford part number - the aftermarket stuff is not lasting?