I have a 1997 Lincoln Mark VIII. I have slow leaks in two tires. I took them to a tire shop and they told me the rims are worn and don't seal anymore. If that's true I would like to buy plain steel rims. Can you tell me what will fit my car. Thank you. Tire size-P225 60R16
Head to a salvage yard. They have Hollander Guides that list theses things and tell what other cars' parts will interchange.
Cast wheels suffer from corrosion that leads to the leaks at the beads. There are sealers you can pour in through the valve stem, that are rather effective, but from that point on, no one will ever be able to clean the inside of the tire good enough for a patch to stick in the event you get a puncture from a nail. Tire shop people hate that messy stuff.
There are also "bead sealers", a thin tar-like material that tire shops can brush onto the beads to seal the rough surfaces. They are not a permanent fix but they do work well.
Rust affects steel wheels too. I'm fighting that with my 22 year old Grand Caravan. Visited a salvage yard in Indiana a few years ago and found two rust-free steel wheels. You also might consider finding two sets of wheels. Pretty cast wheels for summer and steel wheels with snow tires for winter. A lot of people do that up here in Wisconsin where they only know how to throw a ton of salt onto an ounce of snow, then plow it into the ditch.