I was installing my cold air intake and I was connecting the breather hose, I took a look at the intake plenum. Is it just me, or is this thing some sort of plastic? If so, has anyone had any problems with it cracking, etc...?

 

At my work, we have had a number of our Crown Vics w/cracked, leaking
intakes. Yes, they are plastic (at least on the Crown Vics).
Ford had covered a number of them under warranty and cover some
for a slight deductible.
Ford must have changed to aluminum at some point. I have an 03 w/4.6 and I have an aluminum intake. Phew!!

Mike

 

The original on my '99 5.4 was aluminum. The '03 5.4 motor I put in had a plastic one. I was going to keep the aluminum one but decided it was more work than i wanted to to at that point so i kept the plastic one. It seems a little louder than the aluminum but other than that I haven't had a problem and I live in pretty severe climate.

 

The plenum is plastic? like between the throttle body, and the intake manifold? I want to see some pics. I dont believe it.
-Patrick

 

Yes, they are plastic. The whole intake, not just the plenum. Why pics? Simply pop your hood and look. The "plastic" does not absorb heat like the older aluminum manifolds, which results in a slightly cooler air-charge. Plus they are lighter.

 

The 98 manifolds aluminum - plenum's plastic - it has a big rubber boot with snaps that goes around that.

 

yeh i was about to say hes probably talking about the lower plenum.. and ive never heard of those cracking

 

I am having my 98 engine replaced with an 2000 5.4L, the shop I am getting the engine from has a large selection of engines, and I needed to swap the Intake Manifold Valve assembly & plenum to the lower part of an "Aluminum intake". The intake that was on the "2000" had a Composite intake which I figured to cause problems later down the road, so I got an aluminum to match the PI heads.
The Underside of some intakes 4.6/5.4 had a valve inside the plenum in which provided different engine characteristics via.. Torque/HP at different RPM (low/high).


This link came up when I was researching the 5.4 intake manifold, the 4.6 uses the same type of intake "composite material".


http://www.fordmanifoldsettlement.com/faq.html#one


The Class Vehicles were equipped with an engine that contained an air intake manifold made entirely from a nylon-composite material. The plaintiffs in these class action lawsuits allege that the coolant crossover passage of these intake manifolds may crack, resulting in coolant leakage, and that Ford violated state law because it failed to disclose this fact to consumers who bought Class Vehicles. Ford denies these allegations and any wrongdoing.

Peace
RS