I just purchased a used 2002 Honda Accord 4cylinder. My question is, What is the proper procedure for flush the Radiator?

This 99 what the cost to fix head gasket $1000.00,car is $200.00 to $300.00.Put head gasket fix for $35.00 good stuff .

There is a good chance that the fairly new trans rebuild,
is now burnt from the slipping

Going to have to have it towed to a shop of your choice

this is probibly a blockage in the radiator or water pump issue start by flushing the radiator,then check that water is flowing thru the radiator and water system.

suggest you buy radiator flush,follow intructions on can,motor not trashed!! flush system until clear,re-install antifreeze,watch for leaks around radiator

Top speed is hard on a car, at that age of vehicle worn water pump and old old with buildup a bad thermostat and radiator with scale buildup on inside and debris on the outside creates more heat than released. try replacing the thermostat and water pump and doing an flush of the cooling system with an oil change and see if that helps. Also a new radiator cap will hold proper pressure on the system so dont forget that.

put honda brand transmission fluid in the transmission fluid dipstick hole, if this is a 4cylinder, use 2.5 quarts to fill, if 6, use 3 quarts. if you are getting brown oilly substance in the radiator fluid reservoir, this usually means you have a blown head gasket, are you having overheating problems. try draining and filling your radiator with new fluid.

Be sure your radiator/cooling system is full. In many cases there is a bleeder valve to release air. If there is none, 'bleed' air at top radiator hose. Remember, this system is under pressure, you can burn yourself badly if U dont follow proper procedure. Look it up in your repair manual.

On my 1996 Accord (4cylinder), this was caused by a tube inside my radiator overflow tank dropping off into the tank - the radiator would have too little fluid in it, so the fans would run a LONG time after shutting the thing down. The tank is in the front left, a white cap with a black tube running out of the cap to the radiator. Underneath the cap there should be a foot or so of hose - this is what fell off of mine.

Hooked it back up, made sure enough fluid was in the radiator, and no more problem.

The dashboard coolant heat gage will show the high temperature, also.

maybe flush the engine and entry and exit pipes

I need to purchase a fan.