I have a 2004 Mercury Marquis that I bought 5 years ago it has constantly leaked coolant, I had it tuned up and the mechanic told me that I had a cracked intake which I know is a problem with these cars. I would like to put an aluminum intake on it so I dont have this problem again. I cant seem to find one. Any idea where I could find this intake? Thanks!
The intake manifold gaskets seal the intake manifold against the cylinder heads. In addition to sealing engine vacuum, they can also seal engine coolant. So when the gasket wears it won’t seal as well and result in coolant leak. That’s really your issue - the gaskets not the intake manifold construction.
My understanding is you do not want an aluminum or metal intake manifold. You can find some on Summit Racing; like Edlebrock. But from what I've been told those are all designed to be used with supercharger or turbo systems on these cars. I've been told they will heat soak and you'll actually get less out of the engine in terms of performance in naturally aspirated form. I've also been told to use only the Ford Racing Performance Improved (PI) intakes as the aftermarkets have some design flaws with screw mounts for the coils and vacuum leaks.
And you are correct, the intake manifolds have two different problems. The movement of plastic on metal causes the gaskets to roll out of their grooves and fail. Also, the plastic nipple on the intake manifold the heater hose connects to tends to get brittle and crack.
I've got a 2004 Grand Marquis and a 2008 CVPI.
