engine block drains
Team Owner
Joined: May 2004
Posts: 82,175
Likes: 1,319
From: McKinney TX
St. Jude Donor '21-'22-'23-'24
No, I don't think you should do that. Read pages 5-22 and 5-23 of the 2005 owner's manual.
Engine Coolant
The cooling system in your vehicle is filled with
DEX-COOL® engine coolant. This coolant is designed
to remain in your vehicle for five years or 150,000 miles
(240 000 km), whichever occurs first, if you add only
DEX-COOL® extended life coolant.
The following explains your cooling system and how to
add coolant when it is low. If you have a problem
with engine overheating, see Engine Overheating on
page 5-25.
A 50/50 mixture of clean, drinkable water and
DEX-COOL® coolant will:
• Give freezing protection down to −34°F (−37°C).
• Give boiling protection up to 265°F (129°C).
• Protect against rust and corrosion.
• Help keep the proper engine temperature.
• Let the warning lights and gages work as
they should.
Notice: Using coolant other than DEX-COOL® may
cause premature engine, heater core or radiator
corrosion. In addition, the engine coolant may
require changing sooner, at 30,000 miles (50 000 km)
or 24 months, whichever occurs first. Any repairs
would not be covered by your warranty. Always use
DEX-COOL® (silicate-free) coolant in your vehicle.
The cooling system in your vehicle is filled with
DEX-COOL® engine coolant. This coolant is designed
to remain in your vehicle for five years or 150,000 miles
(240 000 km), whichever occurs first, if you add only
DEX-COOL® extended life coolant.
The following explains your cooling system and how to
add coolant when it is low. If you have a problem
with engine overheating, see Engine Overheating on
page 5-25.
A 50/50 mixture of clean, drinkable water and
DEX-COOL® coolant will:
• Give freezing protection down to −34°F (−37°C).
• Give boiling protection up to 265°F (129°C).
• Protect against rust and corrosion.
• Help keep the proper engine temperature.
• Let the warning lights and gages work as
they should.
Notice: Using coolant other than DEX-COOL® may
cause premature engine, heater core or radiator
corrosion. In addition, the engine coolant may
require changing sooner, at 30,000 miles (50 000 km)
or 24 months, whichever occurs first. Any repairs
would not be covered by your warranty. Always use
DEX-COOL® (silicate-free) coolant in your vehicle.
Melting Slicks
Joined: Sep 2005
Posts: 2,670
Likes: 134
From: merritt island fl
C1 of Year Finalist (stock) 2019
2016 C1 of the Year Finalist
2015 C2 of the Year Finalist
If you want to drain the block the easiest way is to loosen the thermostat housing bolts and pop the stat housing away from the water pump. Kind of messy, though. Remove the stat housing totally and remove the stat to drain both block and radiator.
Safety Car
Joined: Aug 2007
Posts: 4,836
Likes: 9
From: Rushsylvania Ohio
Open the radiator drain first and get all that out.
When I did my stainless steel hose install, I bought a small hand siphon pump at Walmart for less than $10. It comes with a couple of long hoses to attach to the pump. If you remove the upper heater hose back at the firewall connection you than then slip the hose from the siphon pump into this heater hose and slide it all the way down to the thermostat housing. Then siphon out the antifreeze. When I did this and then removed the lower radiator hose and housing, not a single drop of antifreeze spilled out. I was ready with a pan and some rags expecting more to run out, but I got it all with the siphon pump.
Safety Car
Joined: Jul 2004
Posts: 3,867
Likes: 307
From: Wantagh,L.I. New York
I just changed mine after 5 years. Got out approx. 8 qts. from the radiator pet ****. Put back 1 gal. Dex-Cool and about 1 gal. water. Good for another 5 years or until the C7 is available, whichever comes first!
Race Director
Joined: Dec 2007
Posts: 19,030
Likes: 6
From: Maumelle Arkansas
St. Jude Donor '13-'14-'15-'16-'17
GM thread says it all
Why change radiator fluid (antifreeze). I still remember lines and shortages at the auto parts stores when winter approached (usually associated with first freeze warning on the weather news) with people scrambling to buy anti freeze.
Anti freeze has been pretty much a permanent fluid for years now, and only needs replacement if you had to drain for repairs.
If GM warrants it for 150,000 miles, that pretty well confirms it will last a lifetime, unless you drive a lot!!
I have never changed anti freeze in any vehicle I owned in the last 45 years, but I typically change vehicles more frequently than every 5 years.
LJ
Anti freeze has been pretty much a permanent fluid for years now, and only needs replacement if you had to drain for repairs.
If GM warrants it for 150,000 miles, that pretty well confirms it will last a lifetime, unless you drive a lot!!
I have never changed anti freeze in any vehicle I owned in the last 45 years, but I typically change vehicles more frequently than every 5 years.
LJ
Melting Slicks
Joined: Jan 2005
Posts: 2,326
Likes: 5
From: louisville "derby city" kentucky
yes, the ls2 has block drains on each side. BUT, you have to remove the starter on the pass. side, and the engine mount and bracket on the drivers side. too much trouble unless you are pulling the engine IMO. just drain the radiator and replace with about two gallons of dexcool. i have an 05 and me and all my friends in the vette club here do this about every two years. another trick i learned from going to the factory is to vaccumn the air from the cooling system to refill it. i use an a/c vaccumn pump and a gauge and ballcock valve. i got a sink stopper from lowe's that fits the fill tank opening. drilled a hole in it and hook up the vac. pump. then after vaccumning it out, shut the valve and connect the hose to the coolant. open valve and it will draw in the coolant with no trapped air. hope this helps, cranky 
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
Safety Car
Joined: Jul 2004
Posts: 3,867
Likes: 307
From: Wantagh,L.I. New York
Why change radiator fluid (antifreeze). I still remember lines and shortages at the auto parts stores when winter approached (usually associated with first freeze warning on the weather news) with people scrambling to buy anti freeze.
Anti freeze has been pretty much a permanent fluid for years now, and only needs replacement if you had to drain for repairs.
If GM warrants it for 150,000 miles, that pretty well confirms it will last a lifetime, unless you drive a lot!!
I have never changed anti freeze in any vehicle I owned in the last 45 years, but I typically change vehicles more frequently than every 5 years.
LJ
Anti freeze has been pretty much a permanent fluid for years now, and only needs replacement if you had to drain for repairs.
If GM warrants it for 150,000 miles, that pretty well confirms it will last a lifetime, unless you drive a lot!!
I have never changed anti freeze in any vehicle I owned in the last 45 years, but I typically change vehicles more frequently than every 5 years.
LJ
Safety Car
Joined: Jul 2004
Posts: 3,867
Likes: 307
From: Wantagh,L.I. New York
You can test the Dexcool with a standard float tester. However you need the strips to check for akaline levels. The Dexcool will probably never freeze, however leaving it in too long could cause an imbalance in the akaline levels and possible cause damage to the many aluminum parts in and around the engine. Head gasket problems are quite common on aluminum engines and are offen caused by tired antifreeze.
Melting Slicks
Joined: Oct 2008
Posts: 2,098
Likes: 8
From: Dayton Ohio
All of my cars get a coolant change once a year. Like others have said, neglected coolant leads to all sorts of problems...radiator, heater core, head gaskets, intake gaskets, etc, etc. Talk to any tech who's done hard time in a GM dealership over the past 10 years. A coolant change is easy and it's cheap insurance.
Long life anti-freeze is a great marketing tool for low maintenance...but I'm still wouldn't leave that stuff in for more than a couple of years. This is even what my GM automotive instructor taught us several years ago.
Long life anti-freeze is a great marketing tool for low maintenance...but I'm still wouldn't leave that stuff in for more than a couple of years. This is even what my GM automotive instructor taught us several years ago.
