2001 Cadillac Cadillac is scraping in the front when I pull out the driveway

Tire pressure monitoring systems didn't exist yet in 2001. We made it over a hundred years without the need for them, but one incident got the lawyers / politicians involved.

A car this age is going to have sagged springs which is normal. Besides bottoming out easily, proper ride height is important for good tire wear. Even when the alignment computer says the adjustments are okay, incorrect ride height puts the suspension geometry in the wrong shape. That makes the wheels tip in and out on top too much as the car goes up and down over bumps, and leads to accelerated tire wear.

The place to start is with an inspection at a tire and alignment shop. They have books that show every car model, where to take the measurements, and what they should be. Most of the time the fix for low ride height is a set of new springs, and an alignment. Chrysler used "torsion bars" for decades which are an adjustable spring. GM started using that design on their trucks but not on their cars. A lot of GM and Ford cars have air springs that self adjust. If you have that system, there may be a leak in the system or some other problem with the air compressor. Ford does a real poor job of making repair parts available for their cars so some aftermarket companies make kits to replace defective air springs with standard coil springs. There's no change in ride quality but repair and maintenance costs go way down. Repair parts for GM cars are easier to find.

I'm not sure what you mean about the tires and wheels but I get rather concerned when they aren't stock. Being a suspension and alignment specialist, I understand a lot more than most car owners, and mechanics who specialize in other fields. There are legal ramifications pertaining to people who raise their trucks and lower their cars. It adversely affects steering response, handling during evasive maneuvers, braking distance, and comfort on long trips. I won't get involved with any vehicle with altered ride height because I could become party to a lawsuit, and my students were not allowed to bring any vehicle into the shop with altered ride height unless it was to correct it.

That is not to scare you or pick on your car. It is simply to reinforce the validity of you wanting to correct this problem. Most people aren't interested in the long detailed story of why lawyers like to find these kinds of modifications on the other guy's car, but if you are, I can paste a copy of my standard explanation. What you need to know is if non-standard wheels are on your car, they must not move the center of the tire in or out from where it was originally, and the outer circumference of the tires must be the same as they were originally. Beyond that, it doesn't matter if the wheels are steel, cast aluminum, chrome, etc. Besides the four things affected by the wheels, if aftermarket replacements have a "deeper offset", meaning the entire wheel / tire is moved out further from the car body, that moves the car's weight out and away from the center of the wheel bearing. That will lead to rapid and repeated wear of the bearing assembly.

The second issue, which you're asking about, is ride height. That keeps the suspension parts in the correct geometry so the wheels move as designed when the car body moves up and down and when you go around corners.

Also, if any vehicle has anti-lock brakes, the outer circumference of all four tires must be the same. The computer expects to see all four wheels rotating at exactly the same speed when you're driving on a straight road. I suspect that's not an issue because you would have mentioned the yellow ABS warning light.

Your comment about the wheels has me wondering if the previous owner purposely lowered the car. If they did not, you simply have sagged, (weak) springs. That's an issue related to how many years the car's weight has been sitting on them, not mileage. You'll know for sure once the car is inspected and measured. If new springs are called for, a conscientious mechanic will suggest a complete strut assembly, often referred to as "quick struts". The strut is like a giant shock absorber but it is also a structural part of the suspension system that holds the wheel straight up and down. To replace just the spring requires removing the strut and disassembling it to get the spring off. That takes time and can be a somewhat dangerous job. Quick struts are that complete assembly already put together so replacing a pair takes less than a half hour. You'll pay more for the parts but you'll save more than that in reduced labor time, ... AND you'll have new struts. Your car already has a nice ride. With new struts and springs, it might take a few hours to become used to the difference, but the ride quality will be even better. There's different grades of struts and shock absorbers. Most of the time the cheapest aftermarket replacements you can get are about equivalent to what came on the car originally from the factory. All the rest are better and offer improved ride characteristics.

As far as damage from scraping, other than paint on the bumper cover, it is unlikely. Critical parts like oil filters, radiators and hoses, and things like that are tucked up inside and fairly well protected. The person who inspects the car will find anything that may have been damaged and will recommend any repairs if needed.

I'm not an expert on either of those vehicles. I live in the middle of Wisconsin where we got dumped on with twice as much snow last winter as normal. My daily driver is a rusty trusty '88 Dodge Grand Caravan that has never been stuck where I couldn't get it unstuck without help. Even one winter with almost bald front tires, it went through the snow like a four-wheel-drive truck. I haven't even bothered to plow my really long driveway unless I'm expecting company.

Now, ... I also have a '95 Grand Caravan with the "redesigned suspension system that makes it ride more like car" B.S. If there's a snowflake anywhere in the county, that van is stuck. It just isn't the same vehicle.

Because of my older van, I have a hard time understanding when friends say they need a four-wheel-drive. If you have your mind made up on one of those two models, I'm not aware of any common failures, but in general, the newer the vehicle, the more ridiculously complicated electrical systems they will have. The insane use of computers for systems that never needed computers before is why I'm hanging on to my '88 van. On average, I would estimate it has needed a minor repair about once every four or five years, (other than tires). Most of my friends have one to five-year-old vehicles, and it is common for them to have $500.00 to $800.00 repair bills more than once a year, and they think that's normal and acceptable.

What I WOULD suggest is if you find a vehicle you're thinking about buying, go to the Rock Auto web site and look up the timing belt or related components. If you find the notation, "interference engine" included in the part description, think real hard before committing to that car. My van has over 415,000 miles and is on its first replacement timing belt. If it breaks, I'll coast to the side of the road, get towed home, pop a new belt on, and go driving. With an interference engine, when the timing belt breaks, the open valves get hit and bent by the pistons as they coast to a stop. That turns my $50.00 repair into about a $1500.00 repair. I don't worry about my belt breaking because that valve damage won't occur.

Be aware too that in the '80s and '90s, Honda recommended replacing the timing belt every 75,000 miles, and they typically broke at 65,000 miles. Those were interference engines, and there were a lot of very unhappy owners. I don't know the failure history on their newer vehicles. I DO know that on Chrysler products, the timing belts rarely break up to 25,000 miles beyond the service recommendations. For other brands, I haven't heard any common horror stories about early failures, but to be safe, you'll want to know the replacement interval recommendation, and don't exceed it.

You might consider asking at a dealership if a computer needs to be replaced on the vehicle you're looking at, does it have to be programmed by the dealer to the specific car. That is a clever trick designed by GM to make lots of money from unsuspecting owners. You want a car that you or your mechanic can buy a good used computer from a salvage yard and pop it in with no programming needed.