How to change radiator drain plug - 1991 GMC Sonoma

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,

The area behind the drain plug on the radiator is likely plugged up with debris. Removing the lower radiator hose will do the same thing and a little faster. You also run the risk of the drain plug leaking if you remove it. Removing the lower hose will prevent this from happening as well. Let me know if you have any questions and I'll do my best to answer them. Thank you for using FixYa.com!

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

There is drain plug on the bottom of your radiator, open the radiator cap and the drain plug , let the coolant drain in safe container. Replace the plug( put it back in ) fill the radiator with Antifreeze ,put the radiator cap back on and let your car run for 30 min with heater on. Let your car cool off, and then recheck if it needs any moore coolant to be added.

Start by using a clean drain pan placed underneath the radiator drain plug, use a 3/8" one foot length of rubber hose on the radiator drain plug and open the drain plug with the other end of the rubber hose in the clean drain pan, this way, if your coolant is clean, you can reuse it. Next, remove the bracket on top of the radiator, remove upper and lower radiator hoses, remove transmission cooling lines from the radiator, then remove the cooling fan(s). At this time the radiator should lift straight out. Check bottom core support and make sure it's straight across. If the bottom core support is bent, this is the best time to get a big ole hammer and straighten it out. I've changed many radiators because of parking blocks, parking blocks are not forgiving on these types of cars. Good luck, Gary

BUY YOUR RADIATOR HOSES FIRST MAKE SURE NEW HOSES MATCH THE OLD HOSES. BUY NEW RADIATOR CLAMPS AND HAVE EXTRA GALLON OF ANTIFREEZE. MAKE SURE ENGINE IS COOL IF YOU GOING TO CHANGE TOP RADIATOR HOSE REMOVE RADIATOR CAP OR OVER FLOW JUG CAP IF YOUR RADIATOR DONT HAVE RADIATOR CAP FIND RADIATOR DRAIN PLUG.PLACE A CATCH PAN.OPEN RADIATOR DRAIN PLUG CATCH ANTIFREEZE. DRAIN HALF ANTIFEEZE IF YOU GOING TO REPLACE TOP HOSE AND DRAIN OUT ALL ANTIFREEZE IF YOU GOING TO CHANGE LOWER COOLANT HOSE TO WATER PUMP.WHEN DONE CLOSE DRAIN PLUG.PUT ANTIFREEZE IN A SAFE PLACE FROM PETS AND KIDS UNTIL JOB DONE. WHEN YOU REMOVE COOLANT REMOVE WATER HOSE CLAMPS THEN REMOVE RADIATOR HOSES PUT NEW RADIATOR HOSES AND CLAMPS ON HOSES TIGHTEN HOSE CLAMPS DONT OVER TIGHTEN. POUR ANTIFREEZE IN RADIATOR.CRANK ENGINE UP CHECK FOR LEAKS.CHECK COOLANT LEVEL WHEN THERMOSTAT OPENS ADD MORE COOLANT AS NEEDED.

Make sure the engine is cold before you change the coolant.
Open the hood, place a container under the radiator, and look for the drain-plug under the radiator. Remove it by turning it counterclockwise. Remove the radiator cap. Once coolant drained out, replace the drain-plug, and put in fresh coolant. You might also remove the coolant reservior and empty it.

Drivers side at the bottom......may face to the rear or to the side of the rad.

It is located at bottom of radiator, you will need 1/2 inch square drive or a 3/16 inch hex drive to open drain valve. Usually on pass. side at bottom end of radiator.

Things you will need:
Radiator coolant mixture (get from garage)
Radiator flush fluid (also from garage)
Distilled water (Or if your me garden hose water ;) )

Take off the radiator cap when engine is COOL. Find the drain plug located in the bottom of the radiator (normaly hand tight) and let it drain out into a catch container. Put the drain plug back in, follow the instructions on the flush container topping the radiator back up. Let engine run as directed on bottle and then carefuly undo the radiator cap using a rag as not to burn yourself. Then remove the plug again and drain out the flush fluid. Then repeat the process with the radiator fluid as instructed on the bottle.

the drain plug is hidden it is located on the lower side of the radiator and that would on the passanger sideof the radiator....all you need is a 1/4 drive arachet and 12mm socket