Coolant flush

Cshurleylt · February 3, 2019

Hey guys new to the forum and a novice to working on vehicles but I am a hands on kind of guy. I'm planning on doing a coolant flush on my 2004 silverado 5.3. I've talked to some guys on another forum and they're telling me I need to drain the engine block drain plugs aswell to do this correctly. Now I'm not knocking their knowledge by any means because they have given me solid advice on other things. But I have read on the web that you don't need to do that so curious if it does need to be done or not. My Hayne's manual says the same thing about the engine block drains. So can anyone tell me that if I wan't to get all the old coolant out if I need to drain at the engine block drain plugs aswell? I planned on doing a flush like this guy did https://www.silveradosierra.com/engine/2009-silverado-100k-coolant-flush-t562729.html#p5588929

But if yall have another way I'm all ears. I plan on replacing the old stuff with Prestone dexcool 50/50. Thanks and sorry for the long post. Looking forward to learning from yall.

jagabom (Esquire) · February 3, 2019

On my 99 - 4.3 I used to take off the overfill tank cap, open the rad drain and rad cap then let the antifreeze drain out. Then I would remove the drain plug from the side without the starter. The one on the starter side was too hard to get at. Close the plug and rad drain valve up. Fill the overflow tank up and also the rad and fill with just water. Start the truck and run it filling with water as required. Run the truck for a couple hours watching the temp gauge and ensuring the water is topped up. Then repeat the whole procedure again. Then fill with antifreeze. I would mix the antifreeze to 60 % just in case there was any water left in the system. Never had a problem and it gets down to -35 or 40 up here in Canada. After 13 years of driving the heater core plugged. Not sure if related or not. Did this every 3 years.

Jim

Edited February 3, 2019 by jagabom