Hi I bought my 93 civic 100k mile
The dealer did not offer free 3 month warranty
I want to have more knowledge for maintaince,
Any one could giveme advice?
Thankd

I would start by reading and following your owners' manual if you have one. If not, check out Ebay or www.factorymanuals.com. Many people insist on going beyond the owners manual, but it is a good place to start especially if you are not taking up car maintenance as a hobby, but just want to do what you need to to avoid unnecessary expense. Keep an eye on your fluids. React promptly to leaks, finding them and fixing them. Try to figure out strange noises and fix them too.

If you plant to do much of the repairs on the car yourself, you need a book. Skip the ones in the parts stores. Instead check the same sources as for the owners manual for a factory shop manual. You can find a much better book for about the same price.

There are little noise from the engine, is it becoz the engine is too old?

Engines do make more noise as they get older. It would be very hard for you to describe them well enough that anybody else here or I could tell whether they mean a real problem that will quickly become expensive to fix, or nothing to worry about. Squeals and tinny rattles may not be a problem. Solid clunks and bongs are more likely to be problems. Good help with a car is hard to come by. Dealers are usually knowledgeable, and honest, but expensive and tend to want to make everything like new. If you could afford that, you wouldn't have bought a 1993. Your best be may be to go where any friends or family have gone and not had problems. Too many people that give advice do not know as much as they think.

As I said, watch the fluids and be careful when you add any, to add the right ones. Oil, water, brake fluid, transmission fluid all have the right place to go. Often the cap tells what should go in it.

I am really a novice for the car and do not know how to check, I guess probably I will go garage at first.
My friend tell me that I should go there after 3 months

Many people that know about cars make fun of the owners manuals. However, they have a wealth of the basic things a novice like you needs. There may be a picture pointing out the dip stick where you check the oil, and another picture of the end of the dip stick showing where the oil level should be.

Look around under the hood. There may be several white plastic things with a cap and you can see a fluid level in them. They may have a full mark molded into them. If you can see the level through the plastic, it is best to leave the cap on unless the level is below the fill mark. If so, check to see if the cap says what to add. There may be one on the fender with a green or orange fluid in it and hoses running to it. That is the radiator overflow. If you take the cap off when it is hot, it may boil out and scald you. Just don't take any cap off when it is hot and you won't get hurt.

Older cars tend to leak fluids. In many cases, it is cheaper to just keep replacing them than to fix the problem. If you run low on oil or coolant, you could ruin the engine, or at least be stranded somewhere. 3 months is much too long to wait to check them. The radiator is as simple as looking at the plastic bottle once a week or better. It may be OK for it to be lower or almost empty when the engine is cold. Its main function is to collect the hot coolant as it expands when the engine warms up. For the oil, you must find the dipstick. It is often a metal cap with metal bent in a loop on top to make a handle. Sometimes it is a plastic cap with the metal fastened to the bottom. When you pull it out, there is a long piece of metal running down to the bottom of the engine. It should have oil on the bottom and some marks. You should pull it out, wipe if off, put it back in, and then take it out and look at it. You can stuff a paper towel or rag somewhere under the hood to wipe it each time. The oil level should be near the top mark. There maybe a separate cap on the top of the engine where you add oil.