Below are some pictures of the undercarriage of a 2008 ford crown victoria police interceptor. When these pictures were taken, the vehicle in question was around 1 year old.

Here's a picture of the aluminum suspension subframe with the steering rack attatched.

Also visible in the picture is the lower portion of the front engine accessory drive. Starting in the 2006 model year, ford introduced the FS-18 air conditioning compressor. Earlier 2003-2005 crownvics used a scroll compressor instead.

Yes, that's an aftermarket siren installed above the radiator. But this car is in active duty police use, so no problems with the law. lol:)

Starting in the 2006 model year, the transmission cooler was integrated into the lower portion of the air conditioning condensor. The external cooler in front of the condensor is for the power steering system.

Part way into the 2006 model year, police interceptors recieved steel lower control arms. The earlier 2003-2006 crownvics had aluminum lower control arms instead. Service parts literature lists the transition date from aluminum to steel as 12/05/05.

The engine starter motor is much easier to access in the 2003 and later crownvics than in the 1992-2002 cars. No longer do you need a foot or two worth of wobble bars to access the bolts.

The routing of the starter wiring changed in the 2005 model year. In the later cars, the starter wiring runs along the passenger side oil pan fasteners. In the pre-2005 cars, the wiring ran along the passenger's side valve cover and down the back of the cylinder head to get to the starter.

One issue with the new front suspension design is that oil pan is not as well protected as in the pre-2003 cars. There have been reports of 2003+ crownvics with less than a thousand miles on the odometer needing a new engine installed due to oil startvation from a mangled oil pan. This is considered collision damage by ford and is not covered under the factory powertrain warranty.

From this angle, the air conditioner accumulator is visible. This part is located on the passenger's frame rail in between the front of the engine and the radiator fan where the suspension idler arm used to be in the pre-2003 cars. Being this close to the ground, the accumulator is exposed to lots of road splash. This is not too bad a thing if the road splash is just rain water, but northeastern united states road splash contains a highly corrosive mixture of chloride road salts during the cold wintertime months too.

Accurate diagnosis of accumulator refrigerant leaks can be confusing for some mechanics because the accumulator is located very close to the radiator and the a/c refrigerant leak tracer dye is a bright fluorescent green color like many engine cooling system antifreezes. This can lead to a person thinking that their crownvic has a leak in the radiator or one of the engine cooling system hoses, when the engine cooling system is actually leak free and the true cause of the bright green drops on their driveway is a leaky a/c accumulator.

Starting in the 2003 model year, ford also redesigned transmission crossmember. This unit is designed to be really stiff for reduced passenger compartment intrusion during side impact collisions.

This is a press fit crossmember that is really wedged into the frame. Many service technicians report using 3 foot long prybars to get enough leverage to remove this part.

You need to remove the e-brake cable before you can remove the crossmember.

Each side of the crossmember has two thru bolts attaching it to the frame

You also need to remove the catalytic converters before you can remove the crossmember

The floorpan under the front passenger's seat remained essentially the same between the 1990-2002 cars and the 2003-2010 cars. This is really convienent if you want to install newer seats in your older crownvic.

The driveshaft has color bands on it for identification purposes when the vehicle is being manufactured.

Here's a closeup of the rear swaybar.

Also visible in the picture are the rear seat belt crash brackets. Starting in the 2003 model year, mounting hooks were added to the lower portion of the seat to accomodate LATCH equipped child car seats too.

The mufflers hangers in the 2003+ cars were completely redesigned. The fuel filter remained essentially unchanged though.

The two small holes in the muffler allow water to drain out of the exhaust system. A crownvic with it's engine running and a good working set of catalytic converters can generate a suprising amount of water in the exhaust pipes as it idles. And yes, those two holes are ford factory installed, they were not drilled into the mufflers by a mechanic after the car was manufactured.

Here's the evaporative emissions charcoal canister on the trunk floor. In some rural police departments, you'll find these components ripped clean off the floor from offroading adventures. It can be a frustrating expierence for a person to purchase a pre-owned police cruiser from auction, only to find a couple hoses hanging loose under their trunk floor and have a check engine light on their dashboard that won't go away.

The fuel pump is easier to access with the exhaust pipes being routed a little differently.

Starting in the 2003 model year, the shock absorbers were relocated outside the frame rail.

The e-brake adjustment mechanism is essentially a re-run of previous model years.

This vehicle is relatively new and still has the suspension spring tear tag on it. This tag lists the spring rate and load along with some other info.

-These pictures were taken with crown victoria internet discussion forums in mind. It's sometimes really difficult to describe an issue without good pictures of the parts in question. And taking good pictures of undercar parts can be really difficult for the a casual shadetree mechanic. For these pictures, tools were used that many backyard mechanics don't have including: a high-end DSLR camera, a commercial 2 post shop lift, and lots of overhead lighting.
-This car has factory installed white paint. Regardless of which color the upper body panels are repainted with paint, the car will always remain white underneath. This is convienent if you're shopping for a "pre-owned" police cruiser. If the color of the underbody panels doesn't match the paint on the doors, roof, trunk, etc then you know that the car has been repainted at some point previously.

-There has been some talk about corrosion. This is a really complex topic that you can find numerous engineering books written about. But in an oversimplified sense, there are a few different corrosion enviroments scattered around the united states.
--The "Rust Belt Car". The winter in these areas gets cold and lots of rock salt and sand are used to clear snow/ice from the roadways. The salt greatly accelerates the rate at which exposed metal corrodes. Lots of abrasive debris is present during the winter from airborne ice particles and sand. The summers in these areas are often rather humid too.
--The "Southern State Car". The winter in these areas is relatively mild. Road salt is not used, but the roads are sanded in some locations. Cars in these states will get light surface rust but nothing like the heavy scaly rust that you'll get in the salt belt. The summers in these areas are sometimes longer and more humid than the rust belt states.
--The "Desert Car". For corrosion to take place, water is required. In an dry arid enviroment like phoenix arizona, metal parts are unable to rust due to lack of water. Plastic and rubber parts often have a rather short life in such an enviroment. Air conditioning system parts often don't fare much better in these high heat enviroments either.

-This car has been a "rust belt" vehicle it's whole life. But it's only a little over a year old, so negligible corrosion is present underneath. The sandblast effect of road debris on the paint coatings is negligible too since the car only has around 20k miles. Being a police interceptor, this vehicle has close to 2000 hours of idle time already, but this mainly effects the powertrain parts rather than body parts. One thing that will never change is that corrosion takes time. Even without any paint, a thick peice of metal won't turn into crumbly rust flakes overnight, this process will take years.