14th Nov 2021, 17:32
In 2003 Ford revised the intake manifold to include an aluminum front crossover/thermostat housing. The rest is still plastic and they can still leak at the rear (symptoms - weeping oil and a slight stumble at idle). What seems like an intimidating job is actually more tedious than difficult - mark the parts so you know where they go back. YouTube is a help.
24th Nov 2015, 16:49
My 2003 Grand Marquis LS has a composite manifold.
They changed FROM metal to composite for model year 1996, and after the number one coolant crossover kept cracking (resulting in tons of failures and a huge recall that we JUST missed getting a reimbursement on by three weeks for our $730+ repair bill on our 1997 Grand Marquis GS in December 2002), they revised the composite manifolds to include a metal coolant crossover and thermostat housing for model year 2002-2011. These revised manifolds can (and do) still fail, but at a MUCH lower rate than the all-composite units (and usually due to failure of the bond between the composite materials and the aluminum crossover, rather than the composites cracking).
When I re-engined the '97 GS in 2011, I moved that revised manifold over from the '97 engine to a '95 T-bird engine (after a cleaning and thorough inspection, it was in excellent shape). The manifold from the T-bird was one of the all-aluminum manifolds from the Essex engine plant (still have it, with throttle body, injectors and fuel rails, but couldn't use it on the GM, as the throttle body faces the wrong way).