How to drain coolant completely?
Thread Starter
Supporting Vendor
Joined: Jul 2003
Posts: 6,486
Likes: 2
From: http://www.mphparts.com 800-364-1975
How to drain coolant completely?
Is there any way to completely drain the engine coolant from the block? I read somewhere that the drain plugs are virtually inaccessible in the C5 LS1 while it's still inside the car. I am not sure if that changed over the years or if it holds true for all years.
Burning Brakes
Joined: Aug 2000
Posts: 1,132
Likes: 1
From: Morganton, NC, USA
I only get about 6 quarts out when I drain the radiator. Some guys recently posted that they can get 10 by raising the rear end. I think the coolant capacity is about 12.6 quarts. There are supposed to be some drain plugs in the block, but are reported to be inaccessible. What I do is force water through the overflow tank with the engine running and the radiator drain **** open. After 10 minutes or so, the discharge is running clear. 
Thread Starter
Supporting Vendor
Joined: Jul 2003
Posts: 6,486
Likes: 2
From: http://www.mphparts.com 800-364-1975
Originally Posted by Dope
Please do me a favor and do not make a post with the words '****' and 'discharge' in it. The immature side of me (most of me) almost knocked over my drink.
Dope
Dope
Thread Starter
Supporting Vendor
Joined: Jul 2003
Posts: 6,486
Likes: 2
From: http://www.mphparts.com 800-364-1975
Originally Posted by 2kbluestreak
I only get about 6 quarts out when I drain the radiator. Some guys recently posted that they can get 10 by raising the rear end. I think the coolant capacity is about 12.6 quarts. There are supposed to be some drain plugs in the block, but are reported to be inaccessible. What I do is force water through the overflow tank with the engine running and the radiator drain **** open. After 10 minutes or so, the discharge is running clear.
Racer
Joined: Jul 2001
Posts: 386
Likes: 0
From: Round Rock, Texas, USA
Originally Posted by Dope
Please do me a favor and do not make a post with the words '****' and 'discharge' in it. The immature side of me (most of me) almost knocked over my drink.
Dope
Dope
If 10 minutes have elapsed and your discharge from your drain **** isn’t clear, should you see a doctor?
Race Director
Joined: Jan 2002
Posts: 19,557
Likes: 1,470
From: I love you & miss you Linda
2017 C7 of the Year Finalist
St. Jude Contributor
Originally Posted by Dope
Please do me a favor and do not make a post with the words '****' and 'discharge' in it. The immature side of me (most of me) almost knocked over my drink.
Dope
Dope
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Burning Brakes
Joined: Nov 2004
Posts: 1,028
Likes: 0
From: Fort Worth Texas
Originally Posted by Dope
Please do me a favor and do not make a post with the words '****' and 'discharge' in it. The immature side of me (most of me) almost knocked over my drink.
Dope
Dope
daaaaannnnnnggggggg.....I almost spit my beer on the screen on that one!
Racer
Joined: Apr 2004
Posts: 320
Likes: 0
From: Valley Alabama
Originally Posted by Dope
Please do me a favor and do not make a post with the words '****' and 'discharge' in it. The immature side of me (most of me) almost knocked over my drink.
Dope
Dope
Funniest thing I've read all day. Thanks for the laugh.
Resident moron
Joined: Jun 2003
Posts: 4,746
Likes: 20
From: Assachusetts
On a serious(?) note, I'd also like to hear about how to do this. Maybe I'll grab my Helms when I get home.
I know that on my LS1 Camaro, I could get to one of the freeze plugs by removing the starter, and I think there's another one on the opposite side (which is probably fairly impossible to get to).
Is this Evans stuff expensive? Ever thought of getting it professionally flushed, using the Evans coolant instead of water?
Might be more costly but easier in the long run.
Dope
I know that on my LS1 Camaro, I could get to one of the freeze plugs by removing the starter, and I think there's another one on the opposite side (which is probably fairly impossible to get to).
Is this Evans stuff expensive? Ever thought of getting it professionally flushed, using the Evans coolant instead of water?
Might be more costly but easier in the long run.
Dope
Burning Brakes
Joined: May 2002
Posts: 970
Likes: 3
From: brooklyn ny
Drain the remainig coolant by removing the drain plug on the block. The one inside of the starter is impossible , the one on the other side of the block is easy to get at. Remove that plug to drain remaining coolant in your system.
Drifting
Joined: Oct 2004
Posts: 1,384
Likes: 8
From: Southwest Virginia
Originally Posted by diynoob
Raising the rear end is an option. The problem is that I am trying to start afresh without any water in the cooling system, at all, so that I can put in some Evans NPG coolant. To work properly it should have less than 3% water in the cooling system which is roughly 1/3 of a quart.
Originally Posted by from thunderracing.com website
Evans Prep Fluid is a waterless flush designed for smaller engines. Prep Fluid should be used when the block drains cannot be removed to drain out water antifreeze trapped in the engine block. Prep Fluid is recommended for all motorcycles converting to NPG+ or NPG. Prep Fluid is not intended to be an operating coolant.
Last edited by SpeedyZ; May 18, 2005 at 09:44 PM.