If I owe a loan, and have not paid it, can a warrant be issued for my arrest?

No. Not simply for failing to pay on alone. Rogue collection agencies sometimes threaten this but the threat itself is a violation of federal law. Do not believe it. If you are concerned or if you believe that there are other relevant facts, you should speak with a local consumer rights attorney.

No. Failing to pay a loan is not a crime. However, if a judgment has been entered against you, and you are summoned or subpoenaed to court for a debtor's exam and don't show up, you can be arrested for contempt.

No you cannot be arrested an imprisoned for a civil debt.. the US has generally outlawed debtors prisons..Albeit there is a few instances where you can get arrested.. such as you get charged with criminal fraud (or pay with a bad check), or you get served with a summons for a deposition or creditors exam and ignore it.

No. There is no debtors prison.

You didn't mention if you have actually been sued yet, in collections, or just late and also what type of loan it is (unsecured or secured). If it's a secured loan like a mortgage, car loan, etc. then they would simply move to try and repossess/foreclose. But assuming you meant a typical unsecured loan or credit card debt, if you cannot reach any settlement with them (which if you haven't tried that, you certainly can with or without an attorney), then they can eventually sue you. If there is no defense, the worst that could happen is that they would get a judgment against you. But they cannot arrest you, take your house, or your car, garnish your wages, attach to your taxes, etc. You have what are called "exemption rights" to protest most of your main assets or at least up to a certain value. After that, if there is nothing left to collect against, while they have a right to try, not much will happen. It does become a lien on any real property you own individually such that if you were to try and refinance or sell later, it would need to be paid off at that time. Also a judgment is good for 10 years and does show up on your credit. You can try to negotiate with them at any time, even after judgment is entered. I hope this provides you at least some relief!