Just buck up and do it. 
Is this an actual method for completely draining coolant/water from the block?
Is this an actual method for completely draining coolant/water from the block? I'm about to flush my coolant and was looking for ways to completely empty the block of the hose water I'll be using during the flush. Of course there's the block drain plugs which are a pain in the *** to get to, but someone mentioned the following method which sounds kind of scary to me but would definitely be a hell of a lot easier. They said to have the engine running with the hose running water through the top while it drains underneath (I'm assuming through the radiator drain with the petcock removed?), when the system is clean they said to turn off the hose and continue to let the water drain while leaving the engine running for a short time to allow all the water to drain from the block. It doesn't sound too safe so I was wondering if this is really something that people do with success? It doesn't damage anything like the water pump or engine? If not, what would be the recommended amount of time to let it drain once the hose has been turned off?
I forgot to mention that the thermostat would already be out of the car during all this.
I forgot to mention that the thermostat would already be out of the car during all this.
Last edited by 00-Z28; Sep 30, 2018 at 01:30 AM. Reason: Additional info required
TECH Addict
Joined: Dec 2017
Posts: 2,180
Likes: 969
That will not "drain" the block. It will "flush" it, to the extent that it will circulate some water through it and somewhat push out the A/F mixture (or whatever else is in it) but the last half-gallon or so will remain trapped in the block on each side, as well as whatever residue is settled down at the bottom.
Best to do it right: pull the drain plugs and let it all out.
Best to do it right: pull the drain plugs and let it all out.
That will not "drain" the block. It will "flush" it, to the extent that it will circulate some water through it and somewhat push out the A/F mixture (or whatever else is in it) but the last half-gallon or so will remain trapped in the block on each side, as well as whatever residue is settled down at the bottom.
Best to do it right: pull the drain plugs and let it all out.
Best to do it right: pull the drain plugs and let it all out.
So running the engine while draining the hose water should remove at least some of what's in the block as opposed to draining it with the engine turned off?
If so, does anyone know at what point I can safely run the engine during the flush while the water is draining?
Sorry for all the questions, I've never done it on this car before.
Y’all new schoolers don’t know how good you got it LOL. Try doing this on an old school SBC with freeze plugs in the block. Removing the block plugs now a days is a breeze compared to the old stuff.
J/k, well sort of...
J/k, well sort of...
SBC’s had drain plugs as well. They actually worked better than the drain plugs on the LS platform. On my Race SBC stuff, I’d thread petcocks into the block down there, as we drained the coolant every Race.
TECH Enthusiast
Joined: Nov 2016
Posts: 711
Likes: 6
From: PNW
The terms “flush” and “drain” are not interchangeable. The operation you described is flushing - however your thread title says draining. Not the same thing at all. You flush a toilet, you drain a tub - which one still has water it in afterwards?
Trending Topics
Obviously reading comprehension is not your thing, If you read the first post he wants to flush the old coolant out with a hose....Then drain the hose water out before refilling with distilled water and fresh coolant.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo Thanks for all the tips guys, I just wound up flushing it twice with distilled water once the hose water was coming out clean, then I added the coolant. Everything worked out fine. Someone on here mentioned that they drain and refill their radiator every 6 months to keep the system fresh, I may start doing that from now on. I also don't have to worry about power steering fluid in the coolant anymore, she's got her own separate cooler now.