Flushing radiator

[igonnahavefun]

Can someone tell me how to flush the radiator on an 03 Sierra with the 5.3. I have looked for a drain and did not see one. Do you fill at the bottle?

[sleepur606]

I read in one of my new LS1 building books that there is a small drain tube kind of hidden on the drivers side tank. When you pull it out, you can point it toward a drain pan and then open the drain valve. The valve should be on the back side (the one you can get at) of the radiator, you should be able to see it if you can see the power steering rack. Just look toward the bottom driver's side corner of the radiator. Not sure about the refill though.

[stevebintenn]

Can someone tell me how to flush the radiator on an 03 Sierra with the 5.3. I have looked for a drain and did not see one. Do you fill at the bottle?

if you cant find it pull the bottom hose on the radiator it will drain out i do not own a 2003 so i do not no for sure but there should be one at the bottom

[Ranger]

I read in one of my new LS1 building books that there is a small drain tube kind of hidden on the drivers side tank. When you pull it out, you can point it toward a drain pan and then open the drain valve. The valve should be on the back side (the one you can get at) of the radiator, you should be able to see it if you can see the power steering rack. Just look toward the bottom driver's side corner of the radiator. Not sure about the refill though.

 

You just close the drain and pour it down the fill/check cap on the top.

[2500HD 8.1]

Sometimes those drains are fragile and it may be easier to just pull the bottom hose to drain it like said above.

[C & A s Dad]

Evan, the radiator drain is on the drivers side right at the at the bottom. On my Yuk I can reach it from the top.

 

Drain the coolant and refill with clean water and a bottle of mild non acidic flush. Drive it for about 15 minutes after it has reached operating temp.

 

Drain it again and refil with clean water and drive it again. The instructions will not tell you to drain it and refill with a 50/50 mix of water and AF. I would suggest you drain it and refill with water one more time to be sure all the flush has been removed.

 

Now you can drain it again and refill with a 50 / 50 mix of Dexcool and water. Some people recommend and use distilled water but some now feel distilled water can contribute to electrolysis. I would tell you to use tap water unless you know your local water is hard and heavy with minerals.

 

I would stongly suggest you add a bottle of LubeGard's Kool It once finished. This product will eliminate all chemical electrolysis which is a problem with most late model vehicles due to the fact that the coolant passes through Iron, Alum, Plastic, Rubber etc etc. We (CARQUEST) sell a great deal of Kool It and recommend it when the system is flushed. It is also recommended in writing by Modine, the industry leader in radiators and heater cores.

[1999 Tahoe 4x4]

Sometimes those drains are fragile and it may be easier to just pull the bottom hose to drain it like said above.

I agree.

 

I have to add that if you drain the radiator with any of the methods described (plug or hose) approx. only 2 gallons will drain. The system however holds apporx. 5 gallons.

So as far as getting the chemical in, that's no problem. To completely get it out is a whole other story.

 

I just did mine yesterday on my 5.7. My drain plug is totally inaccessible. It is about an 1.5 inch away from the wheel well. I would have to drill a hole in to the wheel well to get to it. So I did not mess with it.

 

I removed the thermostat and put the housing back on, opened the upper radiator/hose connection at the radiator. Extended this radiator hose with an adapter and some clamps so, that it leads out of the engine compartment into a bucket. Then with the engine cold and running I started to pour water into the radiator. It took long about 5 minutes/50 gallons after finally undiluted clear water appeared.

I left the hose connection open and filled in 2 gallons of coolant with the engine running while observing the open hose side where still only fresh water appeared. Finally I closed off the system, aired it out and topped it off with appox 1/2 gallon of undiluted antifreeze. So it should be a 50/50 mix now.

[crossusc]

Not sure if in same spot, but on '95 Blazer drain is located:

driver side

front of truck

remove air filter unit

at base of radiator there will be a plastic knob that you turn 90-degrees (counter clockwise).

fluid will come out of another part of the radiator, just "around the corner" on the radiator.

have a platic hose or surgical tubing to attach to the drain, which you can drop down to your drip pan or bucket.