After removing the radiator drain plug and flushing the system, I replaced the plug , added fluid, and now theres a leak coming from the drain plug, and its tight. the plug is plastic with a "built in" flat washer, all one piece, and i'm wondering if there is a rubber or neoprene gasket that goes on the plug ?

First why are you adding it are you overheating? Just a question here for a regular coolant change after you add it you must run the engine to circulate it but when drain it if you didn't drain the engine also there's still fluid in there and that's why only a little bit did you remove the coolant bottle cap when draining it ? Also you obviously had the car jacked up so this raises the engine on an angle keeping a lot of fluid in and you need to remove the lower hose for it to come out on level ground

Removing the drain plug and just letting old coolant drain out and then refilling doesn't really flush it out. It only drains what is in the radiator and it doesn't circulate and flush what is in the engine and heater core.
Take radiator cap off, then take top radiator hose off where it comnects to the radiator..only disconnect that side of the radiator hose aim end of hose downwards and leave it there. Take a wet rag and push it into the radiator where the hose was connected..you don't want to push it in so far you have trouble removing after flushing...the wet rag is just to limit the amount of water that will come out of radiator where hose is no longer attached..crank car and coolant will start to slowly come out the vend of radiator hose aimed downward...have a hose or 4 or 5gallons of water...right after you crank the car pour the water or befilling the radiator with the hose...you want to keep the water going in the radiator as to keep it fulI...replace what is coming out of radiator hose...continue to add water until what is coming out of the radiator hose is clear water.. this way the water is circulating through the entire cooling system and engine. When water is coming out clean...turn car off remove rag from radiator and reconnecupper radiator hose..the drainplug is at the bottom of the radiator on the side of radiator that is on the drivers side of the car....remove drain plug and drain water left in radiator..replace drain plug and crank vehicle and fill radiator with coolant recommended for your vehicle... Sounds more complicated than it really is..other option take to a repair shop and have them flush with machine..usually around 100 bucks at ashop..Iif you have any questions Iwill be glad to answer..

Most radiators have a drain plug on the bottom tank the engine block also has a drain plug . Remove the radiator cap ,open both drains ,let all the coolant run out, if there is no radiator plug remove the lower hose , remove the heater demister hoses, with the heater control on hot flush out all the coolant from the heater radiator. with a garden hose, till the water runs clean, tighten the radiator plug or re fit the hose,put a garden hose into the radiator and flush out till the water at the block plug runs clean ,refit the heater hoses, refit the block plug, fill the radiator from the hose leave the cap off , If it has a overflow tank clean and flush it. start and run engine for 5 minutes top up radiator if needed . stop engine and drain out all water. most important that all old coolant is drained out, only buy the best coolant you can . If you make up your own use only distilled water. keep some to top up with never mix with another brand. Fill radiator with coolant top up over flow tank, run engine top up coolant as needed, refit radiator cap run for another 10 minutes check for leaks,

Once the engine has cooled, locate the radiator drain plug and place a large catch pan underneath it. To expedite the draining process, remove your radiator fill cap to allow air to enter the system. With the cooling system refilled with tap water, replace the radiator fill cap and run the engine allowing it to reach operating temperature.drain radiator,
At this point, if you have opted to purchase a radiator flush kit, you should refill the cooling system with tap water and add the caustic fluid as directed.
Run the engine for as long as the radiator flush kit calls for (usually less than 10 minutes). follow directions on bottle for flushing. if you feel you want to use a T connection just cut into return line, from heater core. then you can use a garden hose to flush system.

Best thing to do is replace the pump as it is make noise telling you that it is coming apart. Unless you have the money to buy another engine you can patch it but a pump is far less expensive than a engine.

Your trans cooler is located inside one of the radiator tanks and would be expensive to replace.
You can either replace the radiator with new or used or cut the lines and install an external cooler as is used for towing. If the cooler in the radiator is leaking, you need to flush the system to remove as much oil as possible or it will cause hoses to soften and fail. Also wise to change trans fluid as well.
Always use double clamps when running rubber lines for cooler so they don't slide apart under pressure.

Your cooling system should be flushed every other year. No, I'm not crazy, but with all the new chemicals they use today, it will literally eat up the rubber hoses and deteriorate the heater core, and the radiator core.
Have a drain pan under the drain plug, or the lower radiator hose, to catch the old fluid. EPA doesn't want you to let it run out onto the ground--it will contaminate Earth!
Make sure the engine is cold! Hot antifreeze burns dramatically and it will burn you, too!
If you can get to the drain plug, (sometimes it's hard to get to) you can put a piece of 3/8 inch hose onto it. Put the other end into the drain pan and open the drain plug. This will let the fluid empty into the drain pan--that way all the fluid will go into the drain pan and not spread out and drip all over the place. Remove the radiator cap.
If you want, and it's much faster, you can remove the lower radiator hose from the radiator. Use caution, though, you don't want to break the neck on the radiator--that's a no-no.
It is better to have the drain plug opened, though, when you start to flush.
A word of caution! Antifreeze/summer coolant is very toxic. Don't get it on the body paint, or on your skin. Wash it off with water! Another thing, it will kill your pets if they drink it, so keep them, and children, away from it, remember, I warned you!:-)
Some vehicles have a vent plug. It's located near the thermostat housing (where the upper radiator hose is connected to). Open this to vent: the fluid will empty out better.
Now will be a good time to inspect the hoses. Look at the heater hoses: are they swelled near the clamps? Do they feel hard, or real soft? If so, replace them. The same with the upper and lower radiator hoses. If your vehicle has a by-pass hose (from the water pump to the thermostat housing) check it also. Don't be skimpy here, a little for a hose now will save a lot later. Replace the hose clamps, too, if they need replacing. I hate those "clip" type, and they are usually in need of replacing.
You can get a "flush kit" at most auto parts stores. Read the instruction as to how to install it. Most of the time you can cut the heater hose going to the waterpump and install it there. They are designed to be a permanent fixture: you can leave it hooked up.
After you have installed the flush kit you need to hook up the garden hose to the fitting. It might be best for you to remove the thermostat, as cool water will close it and restrict flow.
Turn the water faucet on, not too much, and leave the radiator cap off and the drain open. If water spews from the vent plug opening, put it back in.
Crank the engine and let it idle. Watch the fluid coming from the 3/8 tubing. When the fluid is clear as water, ha, you can turn the faucet off and then turn the ignition switch off.
You may need two drain pans to catch all the fluid, plus, you will need to find a place in your city to dispose the fluid: a repair shop, or disposal plant. Do not pour it out on the ground: EPA!!!
Let the vehicle cool down. After the engine is cold you can turn the water faucet on again and reflush. There is no need to restart the engine, just let the water run through the block, heater core, and radiator. Let this go for about two or three minutes, then you can turn the water off and remove the garden hose. Put the cap that came with the kit over the spout after you remove the garden hose...you won't have to remove the flush kit, just leave it there for the next time.
They make chemicals to flush systems that have a lot of rust and deposits in them, but this procedure will work in most cases.
Be sure you have the lower radiator hose clamp tight (if you removed it), and have the drain plug tight (remove the hose if you put one on).
Now you can add your antifreeze/summer coolant. Depending on where you live, most vehicle manufacturers recommend a 50/50 solution. Look in your owner's manual and see what they recommend. If your vehicle holds two gallons of coolant, then you want to put in one gallon of coolant and one gallon of water.
If your vehicle doesn't have a vent plug, you can fill the radiator to the top, then crank the engine. Note: If you removed the thermostat, be sure to reinstall it, I'd recommend installing a new one.
After you crank the engine, let it idle. Watch the radiator filler spout, water may overflow. If it does, put the cap back on. Feel of the upper radiator hose. When it gets warm to hot, then the thermostat has opened and you can remove the radiator cap slowly. If no water tries to escape, then you can remove it and add water.
Most vehicles of late have a plastic reservoir. After you have the radiator full you can fill the reservoir to the line on the side of the container, "full cold", with water.
Now, start the engine again and let it idle. Look for leaks (repair them if you have any) and watch the temperture guage. If you have a light you will have to feel of the upper radiator hose to tell when the engine is at operating temperture: the hose will be very hot. Most vehicles run a 190o thermostat, so you won't be able to hold the hose very long, unless you're a hot-metal worker. :-)
No leaks? Temperture ok? Fluid level full? You're a genius! You are ready to do some more "maintenance" on your vehicle, and you don't have to take it to the repair shop.

The Drain Plug aka Radiator Drain **** has an o-ring on it that does wear-out over time, causing a leak. You can remove and replace these relatively ease. They only turn 1/4th to 1/3rd Counterclockwise to Open and Clockwise to Close. Work on only when the engine is cool. Leave the cap on the radiator to create a suction, decreasing the amount of radiator fluid you will lose. OR drain the Radiator Fluid into a clean container and save for reuse.
Have the new Radiator Drain **** ready for immediately insertion after removing the other leaking Radiator Drain ****. To Remove:
Twist the Radiator Drain **** counterclockwise and pull, continuing to twist counterclockwise removing it.
Immediately install the new Radiator Drain **** by first pushing in and then twisting clockwise to close.
Let me know if this helped, or if you have additional information or questions. Feel free to contact me at FixYa.com!

- Make sure the engine is cold and not running.
- Drain the radiator fluid by opening the drain plug at the bottom of the radiator or for a better/faster drainage and cleaning, carefully remove the bottom radiator hose by first loosening the hose clamp.
- Open the radiator cap and water rinse/flush the radiator core via a garden water hose until you no longer see any dirty water coming out of the bottom hose (or drain plug).
- Flush the radiator over flow (plastic) container by overfilling it with your garden water hose.
- remove garden water hose, carefully refit the bottom radiator hose, tighten the bottom radaitior hose clamp, refit/tighten the radiator drain plug.
- refill the radiator with approved radiator fluid for your climate and also refill the radiator overfow tank to the indicated level..
- Refit radiator cap
- Start your engine until it warms up and check for any water or steam leaks. Refit and or replace any faulty hoses or radiator (regulator) cap!
It is not difficult and have fun!

radiator antifreeze: open drain **** on radiator and drain refill with water re plug and leave radiator cap off. start vehicle. watch when coolant drops or rises drastically as that is the thermostat opening. at that time re open drain **** and fill radiator with hose water at the same time. when water coming out is completely clear again turn vehicle off and drain radiator again. fill with antifreeze and water mix. 50/50

oil: jack up car, find oil plug, directly behind steering rack on oil pan. undo plug and drain oil into container. while oil is draining remove oil filter. wait for oil to drain completely then re-install drain plug and new oil filter(filled with oil) undo oil cap and pour in oil 4.5 quarts on n/a and 5 for turbo. tighten cap and your done.

brake system: dont attempt, use an experienced mechanic as the lines need to be bled in numerous places including inside the car from the abs module mounted behind the passenger seat.
easy brake system: individually bleed brakes while adding fluid until clear fluid comes out. (not efficient)

a/c: do not attempt unless you have an evac pump for ac systems.

clutch: same as easy brake except using the bleed valves at the slave cylinder and on passenger side fender well.

washer fluid: add fluid and squirt a little to make sure there is no air in the line